vendor/tzdb: reimport IANA database+code in a standard layoutvendor/tzdb/tzcode2018evendor/tzdb

I am using a new directory since the layout of both the vendor area
and contrib/ need to be changed.

This is a recommit of r337683 with only code.

40 files changed, 22351 insertions, 0 deletions

diff --git a/CONTRIBUTING b/CONTRIBUTING
new file mode 100644
index 000000000000..0cfc77f61853
--- /dev/null
+++ b/CONTRIBUTING
@@ -0,0 +1,89 @@
+Contributing to the tz code and data
+
+The time zone database is by no means authoritative: governments
+change timekeeping rules erratically and sometimes with little
+warning, the data entries do not cover all of civil time before
+1970, and undoubtedly errors remain in the code and data.  Feel
+free to fill gaps or fix mistakes, and please email improvements
+to tz@iana.org for use in the future.  In your email, please give
+reliable sources that reviewers can check.
+
+-----
+
+Developers can contribute technical changes to the source code and
+data as follows.
+
+To email small changes, please run a POSIX shell command like
+'diff -u old/europe new/europe >myfix.patch', and attach
+myfix.patch to the email.
+
+For more-elaborate changes, please read the theory.html file and browse
+the mailing list archives <https://mm.icann.org/pipermail/tz/> for
+examples of patches that tend to work well.  Additions to
+data should contain commentary citing reliable sources as
+justification.  Citations should use https: URLs if available.
+
+Please submit changes against either the latest release in
+<https://www.iana.org/time-zones> or the master branch of the development
+repository.  The latter is preferred.  If you use Git the following
+workflow may be helpful:
+
+  * Copy the development repository.
+
+      git clone https://github.com/eggert/tz.git
+      cd tz
+
+  * Get current with the master branch.
+
+      git checkout master
+      git pull
+
+  * Switch to a new branch for the changes.  Choose a different
+    branch name for each change set.
+
+      git checkout -b mybranch
+
+  * Sleuth by using 'git blame'.  For example, when fixing data for
+    Africa/Sao_Tome, if the command 'git blame africa' outputs a line
+    '2951fa3b (Paul Eggert 2018-01-08 09:03:13 -0800 1068) Zone
+    Africa/Sao_Tome 0:26:56 - LMT 1884', commit 2951fa3b should
+    provide some justification for the 'Zone Africa/Sao_Tome' line.
+
+  * Edit source files.  Include commentary that justifies the
+    changes by citing reliable sources.
+
+  * Debug the changes, e.g.:
+
+      make check
+      make install
+      ./zdump -v America/Los_Angeles
+
+  * For each separable change, commit it in the new branch, e.g.:
+
+      git add northamerica
+      git commit
+
+    See recent 'git log' output for the commit-message style.
+
+  * Create patch files 0001-*, 0002-*, ...
+
+      git format-patch master
+
+  * After reviewing the patch files, send the patches to tz@iana.org
+    for others to review.
+
+      git send-email master
+
+    For an archived example of such an email, see
+    <https://mm.icann.org/pipermail/tz/2018-February/026122.html>.
+
+  * Start anew by getting current with the master branch again
+    (the second step above).
+
+Please do not create issues or pull requests on GitHub, as the
+proper procedure for proposing and distributing patches is via
+email as illustrated above.
+
+-----
+
+This file is in the public domain.
diff --git a/LICENSE b/LICENSE
new file mode 100644
index 000000000000..8ba4399c622d
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,5 @@
+Unless specified below, all files in the tz code and data (including
+this LICENSE file) are in the public domain.
+
+If the files date.c, newstrftime.3, and strftime.c are present, they
+contain material derived from BSD and use the BSD 3-clause license.
diff --git a/Makefile b/Makefile
new file mode 100644
index 000000000000..21fa4889a3e7
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,1013 @@
+# This file is in the public domain, so clarified as of
+# 2009-05-17 by Arthur David Olson.
+
+# Package name for the code distribution.
+PACKAGE=	tzcode
+
+# Version number for the distribution, overridden in the 'tarballs' rule below.
+VERSION=	unknown
+
+# Email address for bug reports.
+BUGEMAIL=	tz@iana.org
+
+# Choose source data features.  To get new features right away, use:
+#	DATAFORM=	vanguard
+# To wait a while before using new features, to give downstream users
+# time to upgrade zic (the default), use:
+#	DATAFORM=	main
+# To wait even longer for new features, use:
+#	DATAFORM=	rearguard
+DATAFORM=		main
+
+# Change the line below for your time zone (after finding the zone you want in
+# the time zone files, or adding it to a time zone file).
+# Alternatively, if you discover you've got the wrong time zone, you can just
+#	zic -l rightzone
+# to correct things.
+# Use the command
+#	make zonenames
+# to get a list of the values you can use for LOCALTIME.
+
+LOCALTIME=	GMT
+
+# If you want something other than Eastern United States time as a template
+# for handling POSIX-style time zone environment variables,
+# change the line below (after finding the zone you want in the
+# time zone files, or adding it to a time zone file).
+# When a POSIX-style environment variable is handled, the rules in the
+# template file are used to determine "spring forward" and "fall back" days and
+# times; the environment variable itself specifies UT offsets of standard and
+# daylight saving time.
+# Alternatively, if you discover you've got the wrong time zone, you can just
+#	zic -p rightzone
+# to correct things.
+# Use the command
+#	make zonenames
+# to get a list of the values you can use for POSIXRULES.
+# If you want POSIX compatibility, use "America/New_York".
+
+POSIXRULES=	America/New_York
+
+# Also see TZDEFRULESTRING below, which takes effect only
+# if the time zone files cannot be accessed.
+
+
+# Installation locations.
+#
+# The defaults are suitable for Debian, except that if REDO is
+# posix_right or right_posix then files that Debian puts under
+# /usr/share/zoneinfo/posix and /usr/share/zoneinfo/right are instead
+# put under /usr/share/zoneinfo-posix and /usr/share/zoneinfo-leaps,
+# respectively.  Problems with the Debian approach are discussed in
+# the commentary for the right_posix rule (below).
+
+# Destination directory, which can be used for staging.
+# 'make DESTDIR=/stage install' installs under /stage (e.g., to
+# /stage/etc/localtime instead of to /etc/localtime).  Files under
+# /stage are not intended to work as-is, but can be copied by hand to
+# the root directory later.  If DESTDIR is empty, 'make install' does
+# not stage, but installs directly into production locations.
+DESTDIR =
+
+# Everything is installed into subdirectories of TOPDIR, and used there.
+# TOPDIR should be empty (meaning the root directory),
+# or a directory name that does not end in "/".
+# TOPDIR should be empty or an absolute name unless you're just testing.
+TOPDIR =
+
+# The default local time zone is taken from the file TZDEFAULT.
+TZDEFAULT = $(TOPDIR)/etc/localtime
+
+# The subdirectory containing installed program and data files, and
+# likewise for installed files that can be shared among architectures.
+# These should be relative file names.
+USRDIR = usr
+USRSHAREDIR = $(USRDIR)/share
+
+# "Compiled" time zone information is placed in the "TZDIR" directory
+# (and subdirectories).
+# TZDIR_BASENAME should not contain "/" and should not be ".", ".." or empty.
+TZDIR_BASENAME=	zoneinfo
+TZDIR = $(TOPDIR)/$(USRSHAREDIR)/$(TZDIR_BASENAME)
+
+# The "tzselect" and (if you do "make INSTALL") "date" commands go in:
+BINDIR = $(TOPDIR)/$(USRDIR)/bin
+
+# The "zdump" command goes in:
+ZDUMPDIR = $(BINDIR)
+
+# The "zic" command goes in:
+ZICDIR = $(TOPDIR)/$(USRDIR)/sbin
+
+# Manual pages go in subdirectories of. . .
+MANDIR = $(TOPDIR)/$(USRSHAREDIR)/man
+
+# Library functions are put in an archive in LIBDIR.
+LIBDIR = $(TOPDIR)/$(USRDIR)/lib
+
+
+# Types to try, as an alternative to time_t.  int64_t should be first.
+TIME_T_ALTERNATIVES = int64_t int32_t uint32_t uint64_t
+
+# If you want only POSIX time, with time values interpreted as
+# seconds since the epoch (not counting leap seconds), use
+#	REDO=		posix_only
+# below.  If you want only "right" time, with values interpreted
+# as seconds since the epoch (counting leap seconds), use
+#	REDO=		right_only
+# below.  If you want both sets of data available, with leap seconds not
+# counted normally, use
+#	REDO=		posix_right
+# below.  If you want both sets of data available, with leap seconds counted
+# normally, use
+#	REDO=		right_posix
+# below.  POSIX mandates that leap seconds not be counted; for compatibility
+# with it, use "posix_only" or "posix_right".  Use POSIX time on systems with
+# leap smearing; this can work better than unsmeared "right" time with
+# applications that are not leap second aware, and is closer to unsmeared
+# "right" time than unsmeared POSIX time is (e.g., 0.5 vs 1.0 s max error).
+
+REDO=		posix_right
+
+# To install data in text form that has all the information of the binary data,
+# (optionally incorporating leap second information), use
+#	TZDATA_TEXT=	tzdata.zi leapseconds
+# To install text data without leap second information (e.g., because
+# REDO='posix_only'), use
+#	TZDATA_TEXT=	tzdata.zi
+# To avoid installing text data, use
+#	TZDATA_TEXT=
+
+TZDATA_TEXT=	leapseconds tzdata.zi
+
+# For backward-compatibility links for old zone names, use
+#	BACKWARD=	backward
+# If you also want the link US/Pacific-New, even though it is confusing
+# and is planned to be removed from the database eventually, use
+#	BACKWARD=	backward pacificnew
+# To omit these links, use
+#	BACKWARD=
+
+BACKWARD=	backward
+
+# If you want out-of-scope and often-wrong data from the file 'backzone', use
+#	PACKRATDATA=	backzone
+# To omit this data, use
+#	PACKRATDATA=
+
+PACKRATDATA=
+
+# The name of a locale using the UTF-8 encoding, used during self-tests.
+# The tests are skipped if the name does not appear to work on this system.
+
+UTF8_LOCALE=	en_US.utf8
+
+# Since "." may not be in PATH...
+
+YEARISTYPE=	./yearistype
+
+# Non-default libraries needed to link.
+LDLIBS=
+
+# Add the following to the end of the "CFLAGS=" line as needed to override
+# defaults specified in the source code.  "-DFOO" is equivalent to "-DFOO=1".
+#  -DBIG_BANG=-9999999LL if the Big Bang occurred at time -9999999 (see zic.c)
+#  -DDEPRECATE_TWO_DIGIT_YEARS for optional runtime warnings about strftime
+#	formats that generate only the last two digits of year numbers
+#  -DEPOCH_LOCAL if the 'time' function returns local time not UT
+#  -DEPOCH_OFFSET=N if the 'time' function returns a value N greater
+#	than what POSIX specifies, assuming local time is UT.
+#	For example, N is 252460800 on AmigaOS.
+#  -DHAVE_DECL_ASCTIME_R=0 if <time.h> does not declare asctime_r
+#  -DHAVE_DECL_ENVIRON if <unistd.h> declares 'environ'
+#  -DHAVE_DIRECT_H if mkdir needs <direct.h> (MS-Windows)
+#  -DHAVE_GENERIC=0 if _Generic does not work
+#  -DHAVE_GETTEXT if 'gettext' works (e.g., GNU/Linux, FreeBSD, Solaris)
+#  -DHAVE_INCOMPATIBLE_CTIME_R if your system's time.h declares
+#	ctime_r and asctime_r incompatibly with the POSIX standard
+#	(Solaris when _POSIX_PTHREAD_SEMANTICS is not defined).
+#  -DHAVE_INTTYPES_H if you have a non-C99 compiler with <inttypes.h>
+#  -DHAVE_LINK=0 if your system lacks a link function
+#  -DHAVE_LOCALTIME_R=0 if your system lacks a localtime_r function
+#  -DHAVE_LOCALTIME_RZ=0 if you do not want zdump to use localtime_rz
+#	localtime_rz can make zdump significantly faster, but is nonstandard.
+#  -DHAVE_POSIX_DECLS=0 if your system's include files do not declare
+#	functions like 'link' or variables like 'tzname' required by POSIX
+#  -DHAVE_SNPRINTF=0 if your system lacks the snprintf function
+#  -DHAVE_STDBOOL_H if you have a non-C99 compiler with <stdbool.h>
+#  -DHAVE_STDINT_H if you have a non-C99 compiler with <stdint.h>
+#  -DHAVE_STRFTIME_L if <time.h> declares locale_t and strftime_l
+#  -DHAVE_STRDUP=0 if your system lacks the strdup function
+#  -DHAVE_STRTOLL=0 if your system lacks the strtoll function
+#  -DHAVE_SYMLINK=0 if your system lacks the symlink function
+#  -DHAVE_SYS_STAT_H=0 if your compiler lacks a <sys/stat.h>
+#  -DHAVE_SYS_WAIT_H=0 if your compiler lacks a <sys/wait.h>
+#  -DHAVE_TZSET=0 if your system lacks a tzset function
+#  -DHAVE_UNISTD_H=0 if your compiler lacks a <unistd.h>
+#  -Dlocale_t=XXX if your system uses XXX instead of locale_t
+#  -DRESERVE_STD_EXT_IDS if your platform reserves standard identifiers
+#	with external linkage, e.g., applications cannot define 'localtime'.
+#  -Dssize_t=long on hosts like MS-Windows that lack ssize_t
+#  -DSUPPRESS_TZDIR to not prepend TZDIR to file names; this has
+#	security implications and is not recommended for general use
+#  -DTHREAD_SAFE to make localtime.c thread-safe, as POSIX requires;
+#	not needed by the main-program tz code, which is single-threaded.
+#	Append other compiler flags as needed, e.g., -pthread on GNU/Linux.
+#  -Dtime_tz=\"T\" to use T as the time_t type, rather than the system time_t
+#	This is intended for internal use only; it mangles external names.
+#  -DTZ_DOMAIN=\"foo\" to use "foo" for gettext domain name; default is "tz"
+#  -DTZ_DOMAINDIR=\"/path\" to use "/path" for gettext directory;
+#	the default is system-supplied, typically "/usr/lib/locale"
+#  -DTZDEFRULESTRING=\",date/time,date/time\" to default to the specified
+#	DST transitions if the time zone files cannot be accessed
+#  -DUNINIT_TRAP if reading uninitialized storage can cause problems
+#	other than simply getting garbage data
+#  -DUSE_LTZ=0 to build zdump with the system time zone library
+#	Also set TZDOBJS=zdump.o and CHECK_TIME_T_ALTERNATIVES= below.
+#  -DZIC_MAX_ABBR_LEN_WO_WARN=3
+#	(or some other number) to set the maximum time zone abbreviation length
+#	that zic will accept without a warning (the default is 6)
+#  $(GCC_DEBUG_FLAGS) if you are using recent GCC and want lots of checking
+# Select instrumentation via "make GCC_INSTRUMENT='whatever'".
+GCC_INSTRUMENT = \
+  -fsanitize=undefined -fsanitize-address-use-after-scope \
+  -fsanitize-undefined-trap-on-error -fstack-protector
+GCC_DEBUG_FLAGS = -DGCC_LINT -g3 -O3 -fno-common \
+  $(GCC_INSTRUMENT) \
+  -Wall -Wextra \
+  -Walloc-size-larger-than=100000 -Warray-bounds=2 \
+  -Wbad-function-cast -Wcast-align=strict -Wdate-time \
+  -Wdeclaration-after-statement -Wdouble-promotion \
+  -Wformat=2 -Wformat-overflow=2 -Wformat-signedness -Wformat-truncation \
+  -Winit-self -Wjump-misses-init -Wlogical-op \
+  -Wmissing-declarations -Wmissing-prototypes -Wnested-externs \
+  -Wold-style-definition -Woverlength-strings -Wpointer-arith \
+  -Wshadow -Wshift-overflow=2 -Wstrict-prototypes -Wstringop-overflow=4 \
+  -Wstringop-truncation -Wsuggest-attribute=cold \
+  -Wsuggest-attribute=const -Wsuggest-attribute=format \
+  -Wsuggest-attribute=malloc \
+  -Wsuggest-attribute=noreturn -Wsuggest-attribute=pure \
+  -Wtrampolines -Wundef -Wuninitialized -Wunused \
+  -Wvariadic-macros -Wvla -Wwrite-strings \
+  -Wno-address -Wno-format-nonliteral -Wno-sign-compare \
+  -Wno-type-limits -Wno-unused-parameter
+#
+# If your system has a "GMT offset" field in its "struct tm"s
+# (or if you decide to add such a field in your system's "time.h" file),
+# add the name to a define such as
+#	-DTM_GMTOFF=tm_gmtoff
+# to the end of the "CFLAGS=" line.  If not defined, the code attempts to
+# guess TM_GMTOFF from other macros; define NO_TM_GMTOFF to suppress this.
+# Similarly, if your system has a "zone abbreviation" field, define
+#	-DTM_ZONE=tm_zone
+# and define NO_TM_ZONE to suppress any guessing.  These two fields are not
+# required by POSIX, but are widely available on GNU/Linux and BSD systems.
+#
+# The next batch of options control support for external variables
+# exported by tzcode.  In practice these variables are less useful
+# than TM_GMTOFF and TM_ZONE.  However, most of them are standardized.
+# #
+# # To omit or support the external variable "tzname", add one of:
+# #	-DHAVE_TZNAME=0
+# #	-DHAVE_TZNAME=1
+# # to the "CFLAGS=" line.  "tzname" is required by POSIX 1988 and later.
+# # If not defined, the code attempts to guess HAVE_TZNAME from other macros.
+# # Warning: unless time_tz is also defined, HAVE_TZNAME=1 can cause
+# # crashes when combined with some platforms' standard libraries,
+# # presumably due to memory allocation issues.
+# #
+# # To omit or support the external variables "timezone" and "daylight", add
+# #	-DUSG_COMPAT=0
+# #	-DUSG_COMPAT=1
+# # to the "CFLAGS=" line; "timezone" and "daylight" are inspired by
+# # Unix Systems Group code and are required by POSIX 2008 (with XSI) and later.
+# # If not defined, the code attempts to guess USG_COMPAT from other macros.
+# #
+# # To support the external variable "altzone", add
+# #	-DALTZONE
+# # to the end of the "CFLAGS=" line; although "altzone" appeared in
+# # System V Release 3.1 it has not been standardized.
+#
+# If you want functions that were inspired by early versions of X3J11's work,
+# add
+#	-DSTD_INSPIRED
+# to the end of the "CFLAGS=" line.  This arranges for the functions
+# "tzsetwall", "offtime", "timelocal", "timegm", "timeoff",
+# "posix2time", and "time2posix" to be added to the time conversion library.
+# "tzsetwall" is like "tzset" except that it arranges for local wall clock
+# time (rather than the time specified in the TZ environment variable)
+# to be used.
+# "offtime" is like "gmtime" except that it accepts a second (long) argument
+# that gives an offset to add to the time_t when converting it.
+# "timelocal" is equivalent to "mktime".
+# "timegm" is like "timelocal" except that it turns a struct tm into
+# a time_t using UT (rather than local time as "timelocal" does).
+# "timeoff" is like "timegm" except that it accepts a second (long) argument
+# that gives an offset to use when converting to a time_t.
+# "posix2time" and "time2posix" are described in an included manual page.
+# X3J11's work does not describe any of these functions.
+# Sun has provided "tzsetwall", "timelocal", and "timegm" in SunOS 4.0.
+# These functions may well disappear in future releases of the time
+# conversion package.
+#
+# If you don't want functions that were inspired by NetBSD, add
+#	-DNETBSD_INSPIRED=0
+# to the end of the "CFLAGS=" line.  Otherwise, the functions
+# "localtime_rz", "mktime_z", "tzalloc", and "tzfree" are added to the
+# time library, and if STD_INSPIRED is also defined the functions
+# "posix2time_z" and "time2posix_z" are added as well.
+# The functions ending in "_z" (or "_rz") are like their unsuffixed
+# (or suffixed-by-"_r") counterparts, except with an extra first
+# argument of opaque type timezone_t that specifies the time zone.
+# "tzalloc" allocates a timezone_t value, and "tzfree" frees it.
+#
+# If you want to allocate state structures in localtime, add
+#	-DALL_STATE
+# to the end of the "CFLAGS=" line.  Storage is obtained by calling malloc.
+#
+# NIST-PCTS:151-2, Version 1.4, (1993-12-03) is a test suite put
+# out by the National Institute of Standards and Technology
+# which claims to test C and Posix conformance.  If you want to pass PCTS, add
+#	-DPCTS
+# to the end of the "CFLAGS=" line.
+#
+# If you want strict compliance with XPG4 as of 1994-04-09, add
+#	-DXPG4_1994_04_09
+# to the end of the "CFLAGS=" line.  This causes "strftime" to always return
+# 53 as a week number (rather than 52 or 53) for January days before
+# January's first Monday when a "%V" format is used and January 1
+# falls on a Friday, Saturday, or Sunday.
+
+CFLAGS=
+
+# Linker flags.  Default to $(LFLAGS) for backwards compatibility
+# to release 2012h and earlier.
+
+LDFLAGS=	$(LFLAGS)
+
+# For leap seconds, this Makefile uses LEAPSECONDS='-L leapseconds' in
+# submake command lines.  The default is no leap seconds.
+
+LEAPSECONDS=
+
+# The zic command and its arguments.
+
+zic=		./zic
+ZIC=		$(zic) $(ZFLAGS)
+
+ZFLAGS=
+
+# How to use zic to install tz binary files.
+
+ZIC_INSTALL=	$(ZIC) -d '$(DESTDIR)$(TZDIR)' $(LEAPSECONDS)
+
+# The name of a Posix-compliant 'awk' on your system.
+AWK=		awk
+
+# The full path name of a Posix-compliant shell, preferably one that supports
+# the Korn shell's 'select' statement as an extension.
+# These days, Bash is the most popular.
+# It should be OK to set this to /bin/sh, on platforms where /bin/sh
+# lacks 'select' or doesn't completely conform to Posix, but /bin/bash
+# is typically nicer if it works.
+KSHELL=		/bin/bash
+
+# The path where SGML DTDs are kept and the catalog file(s) to use when
+# validating.  The default should work on both Debian and Red Hat.
+SGML_TOPDIR= /usr
+SGML_DTDDIR= $(SGML_TOPDIR)/share/xml/w3c-sgml-lib/schema/dtd
+SGML_SEARCH_PATH= $(SGML_DTDDIR)/REC-html401-19991224
+SGML_CATALOG_FILES= \
+  $(SGML_TOPDIR)/share/doc/w3-recs/html/www.w3.org/TR/1999/REC-html401-19991224/HTML4.cat:$(SGML_TOPDIR)/share/sgml/html/4.01/HTML4.cat
+
+# The name, arguments and environment of a program to validate your web pages.
+# See <http://openjade.sourceforge.net/doc/> for a validator, and
+# <https://validator.w3.org/source/> for a validation library.
+# Set VALIDATE=':' if you do not have such a program.
+VALIDATE = nsgmls
+VALIDATE_FLAGS = -s -B -wall -wno-unused-param
+VALIDATE_ENV = \
+  SGML_CATALOG_FILES='$(SGML_CATALOG_FILES)' \
+  SGML_SEARCH_PATH='$(SGML_SEARCH_PATH)' \
+  SP_CHARSET_FIXED=YES \
+  SP_ENCODING=UTF-8
+
+# This expensive test requires USE_LTZ.
+# To suppress it, define this macro to be empty.
+CHECK_TIME_T_ALTERNATIVES = check_time_t_alternatives
+
+# SAFE_CHAR is a regular expression that matches a safe character.
+# Some parts of this distribution are limited to safe characters;
+# others can use any UTF-8 character.
+# For now, the safe characters are a safe subset of ASCII.
+# The caller must set the shell variable 'sharp' to the character '#',
+# since Makefile macros cannot contain '#'.
+# TAB_CHAR is a single tab character, in single quotes.
+TAB_CHAR=	'	'
+SAFE_CHARSET1=	$(TAB_CHAR)' !\"'$$sharp'$$%&'\''()*+,./0123456789:;<=>?@'
+SAFE_CHARSET2=	'ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\^_`'
+SAFE_CHARSET3=	'abcdefghijklmnopqrstuvwxyz{|}~'
+SAFE_CHARSET=	$(SAFE_CHARSET1)$(SAFE_CHARSET2)$(SAFE_CHARSET3)
+SAFE_CHAR=	'[]'$(SAFE_CHARSET)'-]'
+
+# Non-ASCII non-letters that OK_CHAR allows, as these characters are
+# useful in commentary.  XEmacs 21.5.34 displays them correctly,
+# presumably because they are Latin-1.
+UNUSUAL_OK_CHARSET= °±½¾×
+
+# OK_CHAR matches any character allowed in the distributed files.
+# This is the same as SAFE_CHAR, except that UNUSUAL_OK_CHARSET and
+# multibyte letters are also allowed so that commentary can contain a
+# few safe symbols and people's names and can quote non-English sources.
+# Other non-letters are limited to ASCII renderings for the
+# convenience of maintainers using XEmacs 21.5.34, which by default
+# mishandles Unicode characters U+0100 and greater.
+OK_CHAR=	'[][:alpha:]$(UNUSUAL_OK_CHARSET)'$(SAFE_CHARSET)'-]'
+
+# SAFE_LINE matches a line of safe characters.
+# SAFE_SHARP_LINE is similar, except any OK character can follow '#';
+# this is so that comments can contain non-ASCII characters.
+# OK_LINE matches a line of OK characters.
+SAFE_LINE=	'^'$(SAFE_CHAR)'*$$'
+SAFE_SHARP_LINE='^'$(SAFE_CHAR)'*('$$sharp$(OK_CHAR)'*)?$$'
+OK_LINE=	'^'$(OK_CHAR)'*$$'
+
+# Flags to give 'tar' when making a distribution.
+# Try to use flags appropriate for GNU tar.
+GNUTARFLAGS= --numeric-owner --owner=0 --group=0 --mode=go+u,go-w --sort=name
+TARFLAGS=	`if tar $(GNUTARFLAGS) --version >/dev/null 2>&1; \
+		 then echo $(GNUTARFLAGS); \
+		 else :; \
+		 fi`
+
+# Flags to give 'gzip' when making a distribution.
+GZIPFLAGS=	-9n
+
+###############################################################################
+
+#MAKE=		make
+
+cc=		cc
+CC=		$(cc) -DTZDIR='"$(TZDIR)"'
+
+AR=		ar
+
+# ':' on typical hosts; 'ranlib' on the ancient hosts that still need ranlib.
+RANLIB=		:
+
+TZCOBJS=	zic.o
+TZDOBJS=	zdump.o localtime.o asctime.o strftime.o
+DATEOBJS=	date.o localtime.o strftime.o asctime.o
+LIBSRCS=	localtime.c asctime.c difftime.c
+LIBOBJS=	localtime.o asctime.o difftime.o
+HEADERS=	tzfile.h private.h
+NONLIBSRCS=	zic.c zdump.c
+NEWUCBSRCS=	date.c strftime.c
+SOURCES=	$(HEADERS) $(LIBSRCS) $(NONLIBSRCS) $(NEWUCBSRCS) \
+			tzselect.ksh workman.sh
+MANS=		newctime.3 newstrftime.3 newtzset.3 time2posix.3 \
+			tzfile.5 tzselect.8 zic.8 zdump.8
+MANTXTS=	newctime.3.txt newstrftime.3.txt newtzset.3.txt \
+			time2posix.3.txt \
+			tzfile.5.txt tzselect.8.txt zic.8.txt zdump.8.txt \
+			date.1.txt
+COMMON=		calendars CONTRIBUTING LICENSE Makefile \
+			NEWS README theory.html version
+WEB_PAGES=	tz-art.html tz-how-to.html tz-link.html
+DOCS=		$(MANS) date.1 $(MANTXTS) $(WEB_PAGES)
+PRIMARY_YDATA=	africa antarctica asia australasia \
+		europe northamerica southamerica
+YDATA=		$(PRIMARY_YDATA) etcetera
+NDATA=		systemv factory
+TDATA_TO_CHECK=	$(YDATA) $(NDATA) backward pacificnew
+TDATA=		$(YDATA) $(NDATA) $(BACKWARD)
+ZONETABLES=	zone1970.tab zone.tab
+TABDATA=	iso3166.tab $(TZDATA_TEXT) $(ZONETABLES)
+LEAP_DEPS=	leapseconds.awk leap-seconds.list
+TZDATA_ZI_DEPS=	ziguard.awk zishrink.awk version $(TDATA) $(PACKRATDATA)
+DSTDATA_ZI_DEPS= ziguard.awk $(TDATA) $(PACKRATDATA)
+DATA=		$(TDATA_TO_CHECK) backzone iso3166.tab leap-seconds.list \
+			leapseconds yearistype.sh $(ZONETABLES)
+AWK_SCRIPTS=	checklinks.awk checktab.awk leapseconds.awk \
+			ziguard.awk zishrink.awk
+MISC=		$(AWK_SCRIPTS) zoneinfo2tdf.pl
+TZS_YEAR=	2050
+TZS=		to$(TZS_YEAR).tzs
+TZS_NEW=	to$(TZS_YEAR)new.tzs
+TZS_DEPS=	$(PRIMARY_YDATA) asctime.c localtime.c \
+			private.h tzfile.h zdump.c zic.c
+ENCHILADA=	$(COMMON) $(DOCS) $(SOURCES) $(DATA) $(MISC) $(TZS) tzdata.zi
+
+# Consult these files when deciding whether to rebuild the 'version' file.
+# This list is not the same as the output of 'git ls-files', since
+# .gitignore is not distributed.
+VERSION_DEPS= \
+		calendars CONTRIBUTING LICENSE Makefile NEWS README \
+		africa antarctica asctime.c asia australasia \
+		backward backzone \
+		checklinks.awk checktab.awk \
+		date.1 date.c difftime.c \
+		etcetera europe factory iso3166.tab \
+		leap-seconds.list leapseconds.awk localtime.c \
+		newctime.3 newstrftime.3 newtzset.3 northamerica \
+		pacificnew private.h \
+		southamerica strftime.c systemv theory.html \
+		time2posix.3 tz-art.html tz-how-to.html tz-link.html \
+		tzfile.5 tzfile.h tzselect.8 tzselect.ksh \
+		workman.sh yearistype.sh \
+		zdump.8 zdump.c zic.8 zic.c \
+		ziguard.awk zishrink.awk \
+		zone.tab zone1970.tab zoneinfo2tdf.pl
+
+# And for the benefit of csh users on systems that assume the user
+# shell should be used to handle commands in Makefiles. . .
+
+SHELL=		/bin/sh
+
+all:		tzselect yearistype zic zdump libtz.a $(TABDATA) \
+		  vanguard.zi main.zi rearguard.zi
+
+ALL:		all date $(ENCHILADA)
+
+install:	all $(DATA) $(REDO) $(MANS)
+		mkdir -p '$(DESTDIR)$(BINDIR)' \
+			'$(DESTDIR)$(ZDUMPDIR)' '$(DESTDIR)$(ZICDIR)' \
+			'$(DESTDIR)$(LIBDIR)' \
+			'$(DESTDIR)$(MANDIR)/man3' '$(DESTDIR)$(MANDIR)/man5' \
+			'$(DESTDIR)$(MANDIR)/man8'
+		$(ZIC_INSTALL) -l $(LOCALTIME) -p $(POSIXRULES) \
+			-t '$(DESTDIR)$(TZDEFAULT)'
+		cp -f $(TABDATA) '$(DESTDIR)$(TZDIR)/.'
+		cp tzselect '$(DESTDIR)$(BINDIR)/.'
+		cp zdump '$(DESTDIR)$(ZDUMPDIR)/.'
+		cp zic '$(DESTDIR)$(ZICDIR)/.'
+		cp libtz.a '$(DESTDIR)$(LIBDIR)/.'
+		$(RANLIB) '$(DESTDIR)$(LIBDIR)/libtz.a'
+		cp -f newctime.3 newtzset.3 '$(DESTDIR)$(MANDIR)/man3/.'
+		cp -f tzfile.5 '$(DESTDIR)$(MANDIR)/man5/.'
+		cp -f tzselect.8 zdump.8 zic.8 '$(DESTDIR)$(MANDIR)/man8/.'
+
+INSTALL:	ALL install date.1
+		mkdir -p '$(DESTDIR)$(BINDIR)' '$(DESTDIR)$(MANDIR)/man1'
+		cp date '$(DESTDIR)$(BINDIR)/.'
+		cp -f date.1 '$(DESTDIR)$(MANDIR)/man1/.'
+
+version:	$(VERSION_DEPS)
+		{ (type git) >/dev/null 2>&1 && \
+		  V=`git describe --match '[0-9][0-9][0-9][0-9][a-z]*' \
+				--abbrev=7 --dirty` || \
+		  V='$(VERSION)'; } && \
+		printf '%s\n' "$$V" >$@.out
+		mv $@.out $@
+
+# These files can be tailored by setting BACKWARD, PACKRATDATA, etc.
+vanguard.zi main.zi rearguard.zi: $(DSTDATA_ZI_DEPS)
+		$(AWK) -v DATAFORM=`expr $@ : '\(.*\).zi'` -f ziguard.awk \
+		  $(TDATA) $(PACKRATDATA) >$@.out
+		mv $@.out $@
+tzdata.zi:	$(DATAFORM).zi version
+		version=`sed 1q version` && \
+		  LC_ALL=C $(AWK) -v version="$$version" -f zishrink.awk \
+		    $(DATAFORM).zi >$@.out
+		mv $@.out $@
+
+version.h:	version
+		VERSION=`cat version` && printf '%s\n' \
+		  'static char const PKGVERSION[]="($(PACKAGE)) ";' \
+		  "static char const TZVERSION[]=\"$$VERSION\";" \
+		  'static char const REPORT_BUGS_TO[]="$(BUGEMAIL)";' \
+		  >$@.out
+		mv $@.out $@
+
+zdump:		$(TZDOBJS)
+		$(CC) -o $@ $(CFLAGS) $(LDFLAGS) $(TZDOBJS) $(LDLIBS)
+
+zic:		$(TZCOBJS)
+		$(CC) -o $@ $(CFLAGS) $(LDFLAGS) $(TZCOBJS) $(LDLIBS)
+
+yearistype:	yearistype.sh
+		cp yearistype.sh yearistype
+		chmod +x yearistype
+
+leapseconds:	$(LEAP_DEPS)
+		$(AWK) -f leapseconds.awk leap-seconds.list >$@.out
+		mv $@.out $@
+
+# Arguments to pass to submakes of install_data.
+# They can be overridden by later submake arguments.
+INSTALLARGS = \
+ BACKWARD='$(BACKWARD)' \
+ DESTDIR='$(DESTDIR)' \
+ LEAPSECONDS='$(LEAPSECONDS)' \
+ PACKRATDATA='$(PACKRATDATA)' \
+ TZDEFAULT='$(TZDEFAULT)' \
+ TZDIR='$(TZDIR)' \
+ YEARISTYPE='$(YEARISTYPE)' \
+ ZIC='$(ZIC)'
+
+# 'make install_data' installs one set of tz binary files.
+install_data:	zic leapseconds yearistype tzdata.zi
+		$(ZIC_INSTALL) tzdata.zi
+
+posix_only:
+		$(MAKE) $(INSTALLARGS) LEAPSECONDS= install_data
+
+right_only:
+		$(MAKE) $(INSTALLARGS) LEAPSECONDS='-L leapseconds' \
+			install_data
+
+# In earlier versions of this makefile, the other two directories were
+# subdirectories of $(TZDIR).  However, this led to configuration errors.
+# For example, with posix_right under the earlier scheme,
+# TZ='right/Australia/Adelaide' got you localtime with leap seconds,
+# but gmtime without leap seconds, which led to problems with applications
+# like sendmail that subtract gmtime from localtime.
+# Therefore, the other two directories are now siblings of $(TZDIR).
+# You must replace all of $(TZDIR) to switch from not using leap seconds
+# to using them, or vice versa.
+right_posix:	right_only
+		rm -fr '$(DESTDIR)$(TZDIR)-leaps'
+		ln -s '$(TZDIR_BASENAME)' '$(DESTDIR)$(TZDIR)-leaps' || \
+		  $(MAKE) $(INSTALLARGS) TZDIR='$(TZDIR)-leaps' right_only
+		$(MAKE) $(INSTALLARGS) TZDIR='$(TZDIR)-posix' posix_only
+
+posix_right:	posix_only
+		rm -fr '$(DESTDIR)$(TZDIR)-posix'
+		ln -s '$(TZDIR_BASENAME)' '$(DESTDIR)$(TZDIR)-posix' || \
+		  $(MAKE) $(INSTALLARGS) TZDIR='$(TZDIR)-posix' posix_only
+		$(MAKE) $(INSTALLARGS) TZDIR='$(TZDIR)-leaps' right_only
+
+# This obsolescent rule is present for backwards compatibility with
+# tz releases 2014g through 2015g.  It should go away eventually.
+posix_packrat:
+		$(MAKE) $(INSTALLARGS) PACKRATDATA=backzone posix_only
+
+zones:		$(REDO)
+
+# dummy.zd is not a real file; it is mentioned here only so that the
+# top-level 'make' does not have a syntax error.
+ZDS = dummy.zd
+# Rule used only by submakes invoked by the $(TZS_NEW) rule.
+# It is separate so that GNU 'make -j' can run instances in parallel.
+$(ZDS): zdump
+		./zdump -i -c $(TZS_YEAR) '$(wd)/'$$(expr $@ : '\(.*\).zd') >$@
+
+$(TZS_NEW):	tzdata.zi zdump zic
+		rm -fr tzs.dir
+		mkdir tzs.dir
+		$(zic) -d tzs.dir tzdata.zi
+		$(AWK) '/^L/{print "Link\t" $$2 "\t" $$3}' \
+		   tzdata.zi | LC_ALL=C sort >$@.out
+		wd=`pwd` && \
+		set x `$(AWK) '/^Z/{print "tzs.dir/" $$2 ".zd"}' tzdata.zi \
+			| LC_ALL=C sort -t . -k 2,2` && \
+		shift && \
+		ZDS=$$* && \
+		$(MAKE) wd="$$wd" TZS_YEAR=$(TZS_YEAR) ZDS="$$ZDS" $$ZDS && \
+		sed 's,^TZ=".*tzs\.dir/,TZ=",' $$ZDS >>$@.out
+		rm -fr tzs.dir
+		mv $@.out $@
+
+# If $(TZS) does not already exist (e.g., old-format tarballs), create it.
+# If it exists but 'make check_tzs' fails, a maintainer should inspect the
+# failed output and fix the inconsistency, perhaps by running 'make force_tzs'.
+$(TZS):
+		$(MAKE) force_tzs
+
+force_tzs:	$(TZS_NEW)
+		cp $(TZS_NEW) $(TZS)
+
+libtz.a:	$(LIBOBJS)
+		rm -f $@
+		$(AR) -rc $@ $(LIBOBJS)
+		$(RANLIB) $@
+
+date:		$(DATEOBJS)
+		$(CC) -o $@ $(CFLAGS) $(LDFLAGS) $(DATEOBJS) $(LDLIBS)
+
+tzselect:	tzselect.ksh version
+		VERSION=`cat version` && sed \
+			-e 's|#!/bin/bash|#!$(KSHELL)|g' \
+			-e 's|AWK=[^}]*|AWK=$(AWK)|g' \
+			-e 's|\(PKGVERSION\)=.*|\1='\''($(PACKAGE)) '\''|' \
+			-e 's|\(REPORT_BUGS_TO\)=.*|\1=$(BUGEMAIL)|' \
+			-e 's|TZDIR=[^}]*|TZDIR=$(TZDIR)|' \
+			-e 's|\(TZVERSION\)=.*|\1='"$$VERSION"'|' \
+			<$@.ksh >$@.out
+		chmod +x $@.out
+		mv $@.out $@
+
+check:		check_character_set check_white_space check_links \
+		  check_name_lengths check_sorted \
+		  check_tables check_web check_zishrink check_tzs
+
+check_character_set: $(ENCHILADA)
+	test ! '$(UTF8_LOCALE)' || \
+	! printf 'A\304\200B\n' | \
+	  LC_ALL='$(UTF8_LOCALE)' grep -q '^A.B$$' >/dev/null 2>&1 || { \
+		LC_ALL='$(UTF8_LOCALE)' && export LC_ALL && \
+		sharp='#' && \
+		! grep -Env $(SAFE_LINE) $(MANS) date.1 $(MANTXTS) \
+			$(MISC) $(SOURCES) $(WEB_PAGES) \
+			CONTRIBUTING LICENSE README \
+			version tzdata.zi && \
+		! grep -Env $(SAFE_LINE)'|^UNUSUAL_OK_CHARSET='$(OK_CHAR)'*$$' \
+			Makefile && \
+		! grep -Env $(SAFE_SHARP_LINE) $(TDATA_TO_CHECK) backzone \
+			leapseconds yearistype.sh zone.tab && \
+		! grep -Env $(OK_LINE) $(ENCHILADA); \
+	}
+
+check_white_space: $(ENCHILADA)
+		patfmt=' \t|[\f\r\v]' && pat=`printf "$$patfmt\\n"` && \
+		! grep -En "$$pat" $(ENCHILADA)
+		! grep -n '[[:space:]]$$' \
+			$$(ls $(ENCHILADA) | grep -Fvx leap-seconds.list)
+
+PRECEDES_FILE_NAME = ^(Zone|Link[[:space:]]+[^[:space:]]+)[[:space:]]+
+FILE_NAME_COMPONENT_TOO_LONG = \
+  $(PRECEDES_FILE_NAME)[^[:space:]]*[^/[:space:]]{15}
+
+check_name_lengths: $(TDATA_TO_CHECK) backzone
+		! grep -En '$(FILE_NAME_COMPONENT_TOO_LONG)' \
+			$(TDATA_TO_CHECK) backzone
+
+CHECK_CC_LIST = { n = split($$1,a,/,/); for (i=2; i<=n; i++) print a[1], a[i]; }
+
+check_sorted: backward backzone iso3166.tab zone.tab zone1970.tab
+		$(AWK) '/^Link/ {print $$3}' backward | LC_ALL=C sort -cu
+		$(AWK) '/^Zone/ {print $$2}' backzone | LC_ALL=C sort -cu
+		$(AWK) '/^[^#]/ {print $$1}' iso3166.tab | LC_ALL=C sort -cu
+		$(AWK) '/^[^#]/ {print $$1}' zone.tab | LC_ALL=C sort -c
+		$(AWK) '/^[^#]/ {print substr($$0, 1, 2)}' zone1970.tab | \
+		  LC_ALL=C sort -c
+		$(AWK) '/^[^#]/ $(CHECK_CC_LIST)' zone1970.tab | \
+		  LC_ALL=C sort -cu
+
+check_links:	checklinks.awk $(TDATA_TO_CHECK) tzdata.zi
+		$(AWK) -f checklinks.awk $(TDATA_TO_CHECK)
+		$(AWK) -f checklinks.awk tzdata.zi
+
+check_tables:	checktab.awk $(PRIMARY_YDATA) $(ZONETABLES)
+		for tab in $(ZONETABLES); do \
+		  $(AWK) -f checktab.awk -v zone_table=$$tab $(PRIMARY_YDATA) \
+		    || exit; \
+		done
+
+check_tzs:	$(TZS) $(TZS_NEW)
+		diff -u $(TZS) $(TZS_NEW)
+
+# This checks only the HTML 4.01 strict page.
+# To check the the other pages, use <https://validator.w3.org/>.
+check_web:	tz-how-to.html
+		$(VALIDATE_ENV) $(VALIDATE) $(VALIDATE_FLAGS) tz-how-to.html
+
+# Check that zishrink.awk does not alter the data, and that ziguard.awk
+# preserves main-format data.
+check_zishrink: zic leapseconds $(PACKRATDATA) $(TDATA) \
+		  $(DATAFORM).zi tzdata.zi
+		for type in posix right; do \
+		  mkdir -p time_t.dir/$$type time_t.dir/$$type-t \
+		    time_t.dir/$$type-shrunk && \
+		  case $$type in \
+		    right) leap='-L leapseconds';; \
+	            *) leap=;; \
+		  esac && \
+		  $(ZIC) $$leap -d time_t.dir/$$type $(DATAFORM).zi && \
+		  case $(DATAFORM) in \
+		    main) \
+		      $(ZIC) $$leap -d time_t.dir/$$type-t $(TDATA) && \
+		      $(AWK) '/^Rule/' $(TDATA) | \
+			$(ZIC) $$leap -d time_t.dir/$$type-t - \
+			  $(PACKRATDATA) && \
+		      diff -r time_t.dir/$$type time_t.dir/$$type-t;; \
+		  esac && \
+		  $(ZIC) $$leap -d time_t.dir/$$type-shrunk tzdata.zi && \
+		  diff -r time_t.dir/$$type time_t.dir/$$type-shrunk || exit; \
+		done
+		rm -fr time_t.dir
+
+clean_misc:
+		rm -f core *.o *.out \
+		  date tzselect version.h zdump zic yearistype libtz.a
+clean:		clean_misc
+		rm -fr *.dir *.zi tzdb-*/ $(TZS_NEW)
+
+maintainer-clean: clean
+		@echo 'This command is intended for maintainers to use; it'
+		@echo 'deletes files that may need special tools to rebuild.'
+		rm -f leapseconds version $(MANTXTS) $(TZS) *.asc *.tar.*
+
+names:
+		@echo $(ENCHILADA)
+
+public:		check check_public $(CHECK_TIME_T_ALTERNATIVES) \
+		tarballs signatures
+
+date.1.txt:	date.1
+newctime.3.txt:	newctime.3
+newstrftime.3.txt: newstrftime.3
+newtzset.3.txt:	newtzset.3
+time2posix.3.txt: time2posix.3
+tzfile.5.txt:	tzfile.5
+tzselect.8.txt:	tzselect.8
+zdump.8.txt:	zdump.8
+zic.8.txt:	zic.8
+
+$(MANTXTS):	workman.sh
+		LC_ALL=C sh workman.sh `expr $@ : '\(.*\)\.txt$$'` >$@.out
+		mv $@.out $@
+
+# Set the time stamps to those of the git repository, if available,
+# and if the files have not changed since then.
+# This uses GNU 'touch' syntax 'touch -d@N FILE',
+# where N is the number of seconds since 1970.
+# If git or GNU 'touch' is absent, don't bother to sync with git timestamps.
+# Also, set the timestamp of each prebuilt file like 'leapseconds'
+# to be the maximum of the files it depends on.
+set-timestamps.out: $(ENCHILADA)
+		rm -f $@
+		if (type git) >/dev/null 2>&1 && \
+		   files=`git ls-files $(ENCHILADA)` && \
+		   touch -md @1 test.out; then \
+		  rm -f test.out && \
+		  for file in $$files; do \
+		    if git diff --quiet $$file; then \
+		      time=`git log -1 --format='tformat:%ct' $$file` && \
+		      touch -cmd @$$time $$file; \
+		    else \
+		      echo >&2 "$$file: warning: does not match repository"; \
+		    fi || exit; \
+		  done; \
+		fi
+		touch -cmr `ls -t $(LEAP_DEPS) | sed 1q` leapseconds
+		for file in `ls $(MANTXTS) | sed 's/\.txt$$//'`; do \
+		  touch -cmr `ls -t $$file workman.sh | sed 1q` $$file.txt || \
+		    exit; \
+		done
+		touch -cmr `ls -t $(TZDATA_ZI_DEPS) | sed 1q` tzdata.zi
+		touch -cmr `ls -t $(TZS_DEPS) | sed 1q` $(TZS)
+		touch -cmr `ls -t $(VERSION_DEPS) | sed 1q` version
+		touch $@
+
+# The zics below ensure that each data file can stand on its own.
+# We also do an all-files run to catch links to links.
+
+check_public:
+		$(MAKE) maintainer-clean
+		$(MAKE) CFLAGS='$(GCC_DEBUG_FLAGS)' ALL
+		mkdir -p public.dir
+		for i in $(TDATA_TO_CHECK) tzdata.zi; do \
+		  $(zic) -v -d public.dir $$i 2>&1 || exit; \
+		done
+		$(zic) -v -d public.dir $(TDATA_TO_CHECK)
+		rm -fr public.dir
+
+# Check that the code works under various alternative
+# implementations of time_t.
+check_time_t_alternatives:
+		if diff -q Makefile Makefile 2>/dev/null; then \
+		  quiet_option='-q'; \
+		else \
+		  quiet_option=''; \
+		fi && \
+		wd=`pwd` && \
+		zones=`$(AWK) '/^[^#]/ { print $$3 }' <zone1970.tab` && \
+		for type in $(TIME_T_ALTERNATIVES); do \
+		  mkdir -p time_t.dir/$$type && \
+		  $(MAKE) clean_misc && \
+		  $(MAKE) TOPDIR="$$wd/time_t.dir/$$type" \
+		    CFLAGS='$(CFLAGS) -Dtime_tz='"'$$type'" \
+		    REDO='$(REDO)' \
+		    install && \
+		  diff $$quiet_option -r \
+		    time_t.dir/int64_t/etc \
+		    time_t.dir/$$type/etc && \
+		  diff $$quiet_option -r \
+		    time_t.dir/int64_t/usr/share \
+		    time_t.dir/$$type/usr/share && \
+		  case $$type in \
+		  int32_t) range=-2147483648,2147483647;; \
+		  uint32_t) range=0,4294967296;; \
+		  int64_t) continue;; \
+		  *u*) range=0,10000000000;; \
+		  *) range=-10000000000,10000000000;; \
+		  esac && \
+		  echo checking $$type zones ... && \
+		  time_t.dir/int64_t/usr/bin/zdump -V -t $$range $$zones \
+		      >time_t.dir/int64_t.out && \
+		  time_t.dir/$$type/usr/bin/zdump -V -t $$range $$zones \
+		      >time_t.dir/$$type.out && \
+		  diff -u time_t.dir/int64_t.out time_t.dir/$$type.out \
+		    || exit; \
+		done
+		rm -fr time_t.dir
+
+TRADITIONAL_ASC = \
+  tzcode$(VERSION).tar.gz.asc \
+  tzdata$(VERSION).tar.gz.asc
+ALL_ASC = $(TRADITIONAL_ASC) \
+  tzdata$(VERSION)-rearguard.tar.gz.asc \
+  tzdb-$(VERSION).tar.lz.asc
+
+tarballs traditional_tarballs signatures traditional_signatures: version
+		VERSION=`cat version` && \
+		$(MAKE) VERSION="$$VERSION" $@_version
+
+# These *_version rules are intended for use if VERSION is set by some
+# other means.  Ordinarily these rules are used only by the above
+# non-_version rules, which set VERSION on the 'make' command line.
+tarballs_version: traditional_tarballs_version \
+  tzdata$(VERSION)-rearguard.tar.gz \
+  tzdb-$(VERSION).tar.lz
+traditional_tarballs_version: \
+  tzcode$(VERSION).tar.gz tzdata$(VERSION).tar.gz
+signatures_version: $(ALL_ASC)
+traditional_signatures_version: $(TRADITIONAL_ASC)
+
+tzcode$(VERSION).tar.gz: set-timestamps.out
+		LC_ALL=C && export LC_ALL && \
+		tar $(TARFLAGS) -cf - \
+		    $(COMMON) $(DOCS) $(SOURCES) | \
+		  gzip $(GZIPFLAGS) >$@.out
+		mv $@.out $@
+
+tzdata$(VERSION).tar.gz: set-timestamps.out
+		LC_ALL=C && export LC_ALL && \
+		tar $(TARFLAGS) -cf - $(COMMON) $(DATA) $(MISC) | \
+		  gzip $(GZIPFLAGS) >$@.out
+		mv $@.out $@
+
+tzdata$(VERSION)-rearguard.tar.gz: rearguard.zi set-timestamps.out
+		rm -fr tzdata$(VERSION)-rearguard.dir
+		mkdir tzdata$(VERSION)-rearguard.dir
+		ln $(COMMON) $(DATA) $(MISC) tzdata$(VERSION)-rearguard.dir
+		cd tzdata$(VERSION)-rearguard.dir && \
+		  rm -f $(TDATA) $(PACKRATDATA) version
+		for f in $(TDATA) $(PACKRATDATA); do \
+		  rearf=tzdata$(VERSION)-rearguard.dir/$$f; \
+		  $(AWK) -v DATAFORM=rearguard -f ziguard.awk $$f >$$rearf && \
+		  touch -cmr `ls -t ziguard.awk $$f` $$rearf || exit; \
+		done
+		sed '1s/$$/-rearguard/' \
+		  <version >tzdata$(VERSION)-rearguard.dir/version
+		touch -cmr version tzdata$(VERSION)-rearguard.dir/version
+		LC_ALL=C && export LC_ALL && \
+		  (cd tzdata$(VERSION)-rearguard.dir && \
+		   tar $(TARFLAGS) -cf - $(COMMON) $(DATA) $(MISC) | \
+		     gzip $(GZIPFLAGS)) >$@.out
+		mv $@.out $@
+
+tzdb-$(VERSION).tar.lz: set-timestamps.out
+		rm -fr tzdb-$(VERSION)
+		mkdir tzdb-$(VERSION)
+		ln $(ENCHILADA) tzdb-$(VERSION)
+		touch -cmr `ls -t tzdb-$(VERSION)/* | sed 1q` tzdb-$(VERSION)
+		LC_ALL=C && export LC_ALL && \
+		tar $(TARFLAGS) -cf - tzdb-$(VERSION) | lzip -9 >$@.out
+		mv $@.out $@
+
+tzcode$(VERSION).tar.gz.asc: tzcode$(VERSION).tar.gz
+tzdata$(VERSION).tar.gz.asc: tzdata$(VERSION).tar.gz
+tzdata$(VERSION)-rearguard.tar.gz.asc: tzdata$(VERSION)-rearguard.tar.gz
+tzdb-$(VERSION).tar.lz.asc: tzdb-$(VERSION).tar.lz
+$(ALL_ASC):
+		gpg --armor --detach-sign $?
+
+typecheck:
+		$(MAKE) clean
+		for i in "long long" unsigned; \
+		do \
+			$(MAKE) CFLAGS="-DTYPECHECK -D__time_t_defined -D_TIME_T \"-Dtime_t=$$i\"" ; \
+			./zdump -v Europe/Rome ; \
+			$(MAKE) clean ; \
+		done
+
+zonenames:	tzdata.zi
+		@$(AWK) '/^Z/ { print $$2 } /^L/ { print $$3 }' tzdata.zi
+
+asctime.o:	private.h tzfile.h
+date.o:		private.h
+difftime.o:	private.h
+localtime.o:	private.h tzfile.h
+strftime.o:	private.h tzfile.h
+zdump.o:	version.h
+zic.o:		private.h tzfile.h version.h
+
+.KEEP_STATE:
+
+.PHONY: ALL INSTALL all
+.PHONY: check check_character_set check_links check_name_lengths
+.PHONY: check_public check_sorted check_tables
+.PHONY: check_time_t_alternatives check_tzs check_web check_white_space
+.PHONY: check_zishrink
+.PHONY: clean clean_misc dummy.zd force_tzs
+.PHONY: install install_data maintainer-clean names
+.PHONY: posix_only posix_packrat posix_right
+.PHONY: public right_only right_posix signatures signatures_version
+.PHONY: tarballs tarballs_version
+.PHONY: traditional_signatures traditional_signatures_version
+.PHONY: traditional_tarballs traditional_tarballs_version
+.PHONY: typecheck
+.PHONY: zonenames zones
+.PHONY: $(ZDS)
diff --git a/NEWS b/NEWS
new file mode 100644
index 000000000000..9c445cd0be87
--- /dev/null
+++ b/NEWS
@@ -0,0 +1,4464 @@
+News for the tz database
+
+Release 2018e - 2018-05-01 23:42:51 -0700
+
+  Briefly:
+
+    North Korea switches back to +09 on 2018-05-05.
+    The main format uses negative DST again, for Ireland etc.
+    'make tarballs' now also builds a rearguard tarball.
+    New 's' and 'd' suffixes in SAVE columns of Rule and Zone lines.
+
+  Changes to past and future time stamps
+
+    North Korea switches back from +0830 to +09 on 2018-05-05.
+    (Thanks to Kang Seonghoon, Arthur David Olson, Seo Sanghyeon,
+    and Tim Parenti.)
+
+    Bring back the negative-DST changes of 2018a, except be more
+    compatible with data parsers that do not support negative DST.
+    Also, this now affects historical time stamps in Namibia and the
+    former Czechoslovakia, not just Ireland.  The main format now uses
+    negative DST to model time stamps in Europe/Dublin (from 1971 on),
+    Europe/Prague (1946/7), and Africa/Windhoek (1994/2017).  This
+    does not affect UT offsets, only time zone abbreviations and the
+    tm_isdst flag.  Also, this does not affect rearguard or vanguard
+    formats; effectively the main format now uses vanguard instead of
+    rearguard format.  Data parsers that do not support negative DST
+    can still use data from the rearguard tarball described below.
+
+  Changes to build procedure
+
+    The command 'make tarballs' now also builds the tarball
+    tzdataVERSION-rearguard.tar.gz, which is like tzdataVERSION.tar.gz
+    except that it uses rearguard format intended for trailing-edge
+    data parsers.
+
+  Changes to data format and to code
+
+    The SAVE column of Rule and Zone lines can now have an 's' or 'd'
+    suffix, which specifies whether the adjusted time is standard time
+    or daylight saving time.  If no suffix is given, daylight saving
+    time is used if and only if the SAVE column is nonzero; this is
+    the longstanding behavior.  Although this new feature is not used
+    in tzdata, it could be used to specify the legal time in Namibia
+    1994-2017, as opposed to the popular time (see below).
+
+  Changes to past time stamps
+
+    From 1994 through 2017 Namibia observed DST in winter, not summer.
+    That is, it used negative DST, as Ireland still does.  This change
+    does not affect UTC offsets; it affects only the tm_isdst flag and
+    the abbreviation used during summer, which is now CAT, not WAST.
+    Although (as noted by Michael Deckers) summer and winter time were
+    both simply called "standard time" in Namibian law, in common
+    practice winter time was considered to be DST (as noted by Stephen
+    Colebourne).  The full effect of this change is only in vanguard
+    format; in rearguard and main format, the tm_isdst flag is still
+    zero in winter and nonzero in summer.
+
+    In 1946/7 Czechoslovakia also observed negative DST in winter.
+    The full effect of this change is only in vanguard format; in
+    rearguard and main formats, it is modeled as plain GMT without
+    daylight saving.  Also, the dates of some 1944/5 DST transitions
+    in Czechoslovakia have been changed.
+
+
+Release 2018d - 2018-03-22 07:05:46 -0700
+
+  Briefly:
+
+  Palestine starts DST a week earlier in 2018.
+  Add support for vanguard and rearguard data consumers.
+  Add subsecond precision to source data format, though not to data.
+
+  Changes to future time stamps
+
+    In 2018, Palestine starts DST on March 24, not March 31.
+    Adjust future predictions accordingly.  (Thanks to Sharef Mustafa.)
+
+  Changes to past and future time stamps
+
+    Casey Station in Antarctica changed from +11 to +08 on 2018-03-11
+    at 04:00.  (Thanks to Steffen Thorsen.)
+
+  Changes to past time stamps
+
+    Historical transitions for Uruguay, represented by
+    America/Montevideo, have been updated per official legal documents,
+    replacing previous data mainly originating from the inventions of
+    Shanks & Pottenger.  This has resulted in adjustments ranging from
+    30 to 90 minutes in either direction over at least two dozen
+    distinct periods ranging from one day to several years in length.
+    A mere handful of pre-1991 transitions are unaffected; data since
+    then has come from more reliable contemporaneous reporting.  These
+    changes affect various timestamps in 1920-1923, 1936, 1939,
+    1942-1943, 1959, 1966-1970, 1972, 1974-1980, and 1988-1990.
+    Additionally, Uruguay's pre-standard-time UT offset has been
+    adjusted westward by 7 seconds, from UT-03:44:44 to UT-03:44:51, to
+    match the location of the Observatory of the National Meteorological
+    Institute in Montevideo.
+    (Thanks to Jeremie Bonjour, Tim Parenti, and Michael Deckers.)
+
+    Enderbury and Kiritimati skipped New Year's Eve 1994, not
+    New Year's Day 1995.  (Thanks to Kerry Shetline.)
+
+    Fix the 1912-01-01 transition for Portugal and its colonies.
+    This transition was at 00:00 according to the new UT offset, not
+    according to the old one.  Also assume that Cape Verde switched on
+    the same date as the rest, not in 1907.  This affects
+    Africa/Bissau, Africa/Sao_Tome, Asia/Macau, Atlantic/Azores,
+    Atlantic/Cape_Verde, Atlantic/Madeira, and Europe/Lisbon.
+    (Thanks to Michael Deckers.)
+
+    Fix an off-by-1 error for pre-1913 timestamps in Jamaica and in
+    Turks & Caicos.
+
+  Changes to past time zone abbreviations
+
+    MMT took effect in Uruguay from 1908-06-10, not 1898-06-28.  There
+    is no clock change associated with the transition.
+
+  Changes to build procedure
+
+    The new DATAFORM macro in the Makefile lets the installer choose
+    among three source data formats.  The idea is to lessen downstream
+    disruption when data formats are improved.
+
+    * DATAFORM=vanguard installs from the latest, bleeding-edge
+      format.  DATAFORM=main (the default) installs from the format
+      used in the 'africa' etc. files.  DATAFORM=rearguard installs
+      from a trailing-edge format.  Eventually, elements of today's
+      vanguard format should move to the main format, and similarly
+      the main format's features should eventually move to the
+      rearguard format.
+
+    * In the current version, the main and rearguard formats are
+      identical and match that of 2018c, so this change does not
+      affect default behavior.  The vanguard format currently contains
+      one feature not in the main format: negative SAVE values.  This
+      improves support for Ireland, which uses Irish Standard Time
+      (IST, UTC+01) in summer and GMT (UTC) in winter.  tzcode has
+      supported negative SAVE values for decades, and this feature
+      should move to the main format soon.  However, it will not move
+      to the rearguard format for quite some time because some
+      downstream parsers do not support it.
+
+    * The build procedure constructs three files vanguard.zi, main.zi,
+      and rearguard.zi, one for each format.  The files represent the
+      same data as closely as the formats allow.  These three files
+      are intended for downstream data consumers and are not
+      installed.  Zoneinfo parsers that do not support negative SAVE values
+      should start using rearguard.zi, so that they will be unaffected
+      when the negative-DST feature moves from vanguard to main.
+      Bleeding-edge Zoneinfo parsers that support the new features
+      already can use vanguard.zi; in this respect, current tzcode is
+      bleeding-edge.
+
+    The Makefile should now be safe for parallelized builds, and 'make
+    -j to2050new.tzs' is now much faster on a multiprocessor host
+    with GNU Make.
+
+    When built with -DSUPPRESS_TZDIR, the tzcode library no longer
+    prepends TZDIR/ to file names that do not begin with '/'.  This is
+    not recommended for general use, due to its security implications.
+    (From a suggestion by Manuela Friedrich.)
+
+  Changes to code
+
+    zic now accepts subsecond precision in expressions like
+    00:19:32.13, which is approximately the legal time of the
+    Netherlands from 1835 to 1937.  However, because it is
+    questionable whether the few recorded uses of non-integer offsets
+    had subsecond precision in practice, there are no plans for tzdata
+    to use this feature.  (Thanks to Steve Allen for pointing out
+    the limitations of historical data in this area.)
+
+    The code is a bit more portable to MS-Windows.  Installers can
+    compile with -DRESERVE_STD_EXT_IDS on MS-Windows platforms that
+    reserve identifiers like 'localtime'.  (Thanks to Manuela
+    Friedrich).
+
+  Changes to documentation and commentary
+
+    theory.html now outlines tzdb's extensions to POSIX's model for
+    civil time, and has a section "POSIX features no longer needed"
+    that lists POSIX API components that are now vestigial.
+    (From suggestions by Steve Summit.)  It also better distinguishes
+    time zones from tz regions.  (From a suggestion by Guy Harris.)
+
+    Commentary is now more consistent about using the phrase "daylight
+    saving time", to match the C name tm_isdst.  Daylight saving time
+    need not occur in summer, and need not have a positive offset from
+    standard time.
+
+    Commentary about historical transitions in Uruguay has been expanded
+    with links to many relevant legal documents.
+    (Thanks to Tim Parenti.)
+
+    Commentary now uses some non-ASCII characters with Unicode value
+    less than U+0100, as they can be useful and should work even with
+    older editors such as XEmacs.
+
+
+Release 2018c - 2018-01-22 23:00:44 -0800
+
+  Briefly:
+  Revert Irish changes that relied on negative SAVE values.
+
+  Changes to tm_isdst
+
+    Revert the 2018a change to Europe/Dublin.  As before, this change
+    does not affect UT offsets or abbreviations; it affects only
+    whether timestamps are considered to be standard time or
+    daylight-saving time, as expressed in the tm_isdst flag of C's
+    struct tm type.  This reversion is intended to be a temporary
+    workaround for problems discovered with downstream uses of
+    releases 2018a and 2018b, which implemented Irish time by using
+    negative SAVE values in the Eire rules of the 'europe' file.
+    Although negative SAVE values have been part of tzcode for many
+    years and are supported by many platforms, they were not
+    documented before 2018a and ICU and OpenJDK do not currently
+    support them.  A mechanism to export data to platforms lacking
+    support for negative DST is planned to be developed before the
+    change is reapplied.  (Problems reported by Deborah Goldsmith and
+    Stephen Colebourne.)
+
+  Changes to past time stamps
+
+    Japanese DST transitions (1948-1951) were Sundays at 00:00, not
+    Saturdays or Sundays at 02:00.  (Thanks to Takayuki Nikai.)
+
+  Changes to build procedure
+
+    The build procedure now works around mawk 1.3.3's lack of support
+    for character class expressions.  (Problem reported by Ohyama.)
+
+
+Release 2018b - 2018-01-17 23:24:48 -0800
+
+  Briefly:
+  Fix a packaging problem in tz2018a, which was missing 'pacificnew'.
+
+  Changes to build procedure
+
+    The distribution now contains the file 'pacificnew' again.
+    This file was inadvertantly omitted in the 2018a distribution.
+    (Problem reported by Matias Fonzo.)
+
+
+Release 2018a - 2018-01-12 22:29:21 -0800
+
+  Briefly:
+  São Tomé and Príncipe switched from +00 to +01.
+  Brazil's DST will now start on November's first Sunday.
+  Ireland's standard time is now in the summer, not the winter.
+  Use Debian-style installation locations, instead of 4.3BSD-style.
+  New zic option -t.
+
+  Changes to past and future time stamps
+
+    São Tomé and Príncipe switched from +00 to +01 on 2018-01-01 at
+    01:00.  (Thanks to Steffen Thorsen and Michael Deckers.)
+
+  Changes to future time stamps
+
+    Starting in 2018 southern Brazil will begin DST on November's
+    first Sunday instead of October's third Sunday.  (Thanks to
+    Steffen Thorsen.)
+
+  Changes to past time stamps
+
+    A discrepancy of 4 s in timestamps before 1931 in South Sudan has
+    been corrected.  The 'backzone' and 'zone.tab' files did not agree
+    with the 'africa' and 'zone1970.tab' files.  (Problem reported by
+    Michael Deckers.)
+
+    The abbreviation invented for Bolivia Summer Time (1931-2) is now
+    BST instead of BOST, to be more consistent with the convention
+    used for Latvian Summer Time (1918-9) and for British Summer Time.
+
+  Changes to tm_isdst
+
+    Change Europe/Dublin so that it observes Irish Standard Time (UT
+    +01) in summer and GMT (as negative daylight-saving) in winter,
+    instead of observing standard time (GMT) in winter and Irish
+    Summer Time (UT +01) in summer.  This change does not affect UT
+    offsets or abbreviations; it affects only whether timestamps are
+    considered to be standard time or daylight-saving time, as
+    expressed in the tm_isdst flag of C's struct tm type.
+    (Discrepancy noted by Derick Rethans.)
+
+  Changes to build procedure
+
+    The default installation locations have been changed to mostly
+    match Debian circa 2017, instead of being designed as an add-on to
+    4.3BSD circa 1986.  This affects the Makefile macros TOPDIR,
+    TZDIR, MANDIR, and LIBDIR.  New Makefile macros TZDEFAULT, USRDIR,
+    USRSHAREDIR, BINDIR, ZDUMPDIR, and ZICDIR let installers tailor
+    locations more precisely.  (This responds to suggestions from
+    Brian Inglis and from Steve Summit.)
+
+    The default installation procedure no longer creates the
+    backward-compatibility link US/Pacific-New, which causes
+    confusion during user setup (e.g., see Debian bug 815200).
+    Use 'make BACKWARD="backward pacificnew"' to create the link
+    anyway, for now.  Eventually we plan to remove the link entirely.
+
+    tzdata.zi now contains a version-number comment.
+    (Suggested by Tom Lane.)
+
+    The Makefile now quotes values like BACKWARD more carefully when
+    passing them to the shell.  (Problem reported by Zefram.)
+
+    Builders no longer need to specify -DHAVE_SNPRINTF on platforms
+    that have snprintf and use pre-C99 compilers.  (Problem reported
+    by Jon Skeet.)
+
+  Changes to code
+
+    zic has a new option -t FILE that specifies the location of the
+    file that determines local time when TZ is unset.  The default for
+    this location can be configured via the new TZDEFAULT makefile
+    macro, which defaults to /etc/localtime.
+
+    Diagnostics and commentary now distinguish UT from UTC more
+    carefully; see theory.html for more information about UT vs UTC.
+
+    zic has been ported to GCC 8's -Wstringop-truncation option.
+    (Problem reported by Martin Sebor.)
+
+  Changes to documentation and commentary
+
+    The zic man page now documents the longstanding behavior that
+    times and years can be out of the usual range, with negative times
+    counting backwards from midnight and with year 0 preceding year 1.
+    (Problem reported by Michael Deckers.)
+
+    The theory.html file now mentions the POSIX limit of six chars
+    per abbreviation, and lists alphabetic abbreviations used.
+
+    The files tz-art.htm and tz-link.htm have been renamed to
+    tz-art.html and tz-link.html, respectively, for consistency with
+    other file names and to simplify web server configuration.
+
+
+Release 2017c - 2017-10-20 14:49:34 -0700
+
+  Briefly:
+  Northern Cyprus switches from +03 to +02/+03 on 2017-10-29.
+  Fiji ends DST 2018-01-14, not 2018-01-21.
+  Namibia switches from +01/+02 to +02 on 2018-04-01.
+  Sudan switches from +03 to +02 on 2017-11-01.
+  Tonga likely switches from +13/+14 to +13 on 2017-11-05.
+  Turks & Caicos switches from -04 to -05/-04 on 2018-11-04.
+  A new file tzdata.zi now holds a small text copy of all data.
+  The zic input format has been regularized slightly.
+
+  Changes to future time stamps
+
+    Northern Cyprus has decided to resume EU rules starting
+    2017-10-29, thus reinstituting winter time.
+
+    Fiji ends DST 2018-01-14 instead of the 2018-01-21 previously
+    predicted.  (Thanks to Dominic Fok.)  Adjust future predictions
+    accordingly.
+
+    Namibia will switch from +01 with DST to +02 all year on
+    2017-09-03 at 02:00.  This affects UT offsets starting 2018-04-01
+    at 02:00.  (Thanks to Steffen Thorsen.)
+
+    Sudan will switch from +03 to +02 on 2017-11-01.  (Thanks to Ahmed
+    Atyya and Yahia Abdalla.)  South Sudan is not switching, so
+    Africa/Juba is no longer a link to Africa/Khartoum.
+
+    Tonga has likely ended its experiment with DST, and will not
+    adjust its clocks on 2017-11-05.  Although Tonga has not announced
+    whether it will continue to observe DST, the IATA is assuming that
+    it will not.  (Thanks to David Wade.)
+
+    Turks & Caicos will switch from -04 all year to -05 with US DST on
+    2018-03-11 at 03:00.  This affects UT offsets starting 2018-11-04
+    at 02:00.  (Thanks to Steffen Thorsen.)
+
+  Changes to past time stamps
+
+    Namibia switched from +02 to +01 on 1994-03-21, not 1994-04-03.
+    (Thanks to Arthur David Olson.)
+
+    Detroit did not observe DST in 1967.
+
+    Use railway time for Asia/Kolkata before 1941, by switching to
+    Madras local time (UT +052110) in 1870, then to IST (UT +0530) in
+    1906.  Also, treat 1941-2's +0630 as DST, like 1942-5.
+
+    Europe/Dublin's 1946 and 1947 fallback transitions occurred at
+    02:00 standard time, not 02:00 DST.  (Thanks to Michael Deckers.)
+
+    Pacific/Apia and Pacific/Pago_Pago switched from Antipodean to
+    American time in 1892, not 1879.  (Thanks to Michael Deckers.)
+
+    Adjust the 1867 transition in Alaska to better reflect the
+    historical record, by changing it to occur on 1867-10-18 at 15:30
+    Sitka time rather than at the start of 1867-10-17 local time.
+    Although strictly speaking this is accurate only for Sitka,
+    the rest of Alaska's blanks need to be filled in somehow.
+
+    Fix off-by-one errors in UT offsets for Adak and Nome before 1867.
+    (Thanks to Michael Deckers.)
+
+    Add 7 s to the UT offset in Asia/Yangon before 1920.
+
+  Changes to zone names
+
+    Remove Canada/East-Saskatchewan from the 'backward' file, as it
+    exceeded the 14-character limit and was an unused misnomer anyway.
+
+  Changes to build procedure
+
+    To support applications that prefer to read time zone data in text
+    form, two zic input files tzdata.zi and leapseconds are now
+    installed by default.  The commands 'zic tzdata.zi' and 'zic -L
+    leapseconds tzdata.zi' can reproduce the tzdata binary files
+    without and with leap seconds, respectively.  To prevent these two
+    new files from being installed, use 'make TZDATA_TEXT=', and to
+    suppress leap seconds from the tzdata text installation, use 'make
+    TZDATA_TEXT=tzdata.zi'.
+
+    'make BACKWARD=' now suppresses backward-compatibility names
+    like 'US/Pacific' that are defined in the 'backward' and
+    'pacificnew' files.
+
+    'make check' now works on systems that lack a UTF-8 locale,
+    or that lack the nsgmls program.  Set UTF8_LOCALE to configure
+    the name of a UTF-8 locale, if you have one.
+
+    Y2K runtime checks are no longer enabled by default.  Add
+    -DDEPRECATE_TWO_DIGIT_YEARS to CFLAGS to enable them, instead of
+    adding -DNO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU
+    to disable them.  (New name suggested by Brian Inglis.)
+
+    The build procedure for zdump now works on AIX 7.1.
+    (Problem reported by Kees Dekker.)
+
+  Changes to code
+
+    zic and the reference runtime now reject multiple leap seconds
+    within 28 days of each other, or leap seconds before the Epoch.
+    As a result, support for double leap seconds, which was
+    obsolescent and undocumented, has been removed.  Double leap
+    seconds were an error in the C89 standard; they have never existed
+    in civil timekeeping.  (Thanks to Robert Elz and Bradley White for
+    noticing glitches in the code that uncovered this problem.)
+
+    zic now warns about use of the obsolescent and undocumented -y
+    option, and about use of the obsolescent TYPE field of Rule lines.
+
+    zic now allows unambiguous abbreviations like "Sa" and "Su" for
+    weekdays; formerly it rejected them due to a bug.  Conversely, zic
+    no longer considers non-prefixes to be abbreviations; for example,
+    it no longer accepts "lF" as an abbreviation for "lastFriday".
+    Also, zic warns about the undocumented usage with a "last-"
+    prefix, e.g., "last-Fri".
+
+    Similarly, zic now accepts the unambiguous abbreviation "L" for
+    "Link" in ordinary context and for "Leap" in leap-second context.
+    Conversely, zic no longer accepts non-prefixes such as "La" as
+    abbreviations for words like "Leap".
+
+    zic no longer accepts leap second lines in ordinary input, or
+    ordinary lines in leap second input.  Formerly, zic sometimes
+    warned about this undocumented usage and handled it incorrectly.
+
+    The new macro HAVE_TZNAME governs whether the tzname external
+    variable is exported, instead of USG_COMPAT.  USG_COMPAT now
+    governs only the external variables "timezone" and "daylight".
+    This change is needed because the three variables are not in the
+    same category: although POSIX requires tzname, it specifies the
+    other two variables as optional.  Also, USG_COMPAT is now 1 or 0:
+    if not defined, the code attempts to guess it from other macros.
+
+    localtime.c and difftime.c no longer require stdio.h, and .c files
+    other than zic.c no longer require sys/wait.h.
+
+    zdump.c no longer assumes snprintf.  (Reported by Jonathan Leffler.)
+
+    Calculation of time_t extrema works around a bug in GCC 4.8.4
+    (Reported by Stan Shebs and Joseph Myers.)
+
+    zic.c no longer mistranslates formats of line numbers in non-English
+    locales.  (Problem reported by Benno Schulenberg.)
+
+    Several minor changes have been made to the code to make it a
+    bit easier to port to MS-Windows and Solaris.  (Thanks to Kees
+    Dekker for reporting the problems.)
+
+  Changes to documentation and commentary
+
+    The two new files 'theory.html' and 'calendars' contain the
+    contents of the removed file 'Theory'.  The goal is to document
+    tzdb theory more accessibly.
+
+    The zic man page now documents abbreviation rules.
+
+    tz-link.htm now covers how to apply tzdata changes to clients.
+    (Thanks to Jorge Fábregas for the AIX link.)  It also mentions MySQL.
+
+    The leap-seconds.list URL has been updated to something that is
+    more reliable for tzdb.  (Thanks to Tim Parenti and Brian Inglis.)
+
+Release 2017b - 2017-03-17 07:30:38 -0700
+
+  Briefly: Haiti has resumed DST.
+
+  Changes to past and future time stamps
+
+    Haiti resumed observance of DST in 2017.  (Thanks to Steffen Thorsen.)
+
+  Changes to past time stamps
+
+    Liberia changed from -004430 to +00 on 1972-01-07, not 1972-05-01.
+
+    Use "MMT" to abbreviate Liberia's time zone before 1972, as "-004430"
+    is one byte over the POSIX limit.  (Problem reported by Derick Rethans.)
+
+  Changes to code
+
+    The reference localtime implementation now falls back on the
+    current US daylight-saving transition rules rather than the
+    1987-2006 rules.  This fallback occurs only when (1) the TZ
+    environment variable's value has a name like "AST4ADT" that asks
+    for daylight saving time but does not specify the rules, (2) there
+    is no file by that name, and (3) the TZDEFRULES file cannot be
+    loaded.  (Thanks to Tom Lane.)
+
+
+Release 2017a - 2017-02-28 00:05:36 -0800
+
+  Briefly: Southern Chile moves from -04/-03 to -03, and Mongolia
+  discontinues DST.
+
+  Changes to future time stamps
+
+    Mongolia no longer observes DST.  (Thanks to Ganbold Tsagaankhuu.)
+
+    Chile's Region of Magallanes moves from -04/-03 to -03 year-round.
+    Its clocks diverge from America/Santiago starting 2017-05-13 at
+    23:00, hiving off a new zone America/Punta_Arenas.  Although the
+    Chilean government says this change expires in May 2019, for now
+    assume it's permanent.  (Thanks to Juan Correa and Deborah
+    Goldsmith.)  This also affects Antarctica/Palmer.
+
+  Changes to past time stamps
+
+    Fix many entries for historical time stamps for Europe/Madrid
+    before 1979, to agree with tables compiled by Pere Planesas of the
+    National Astronomical Observatory of Spain.  As a side effect,
+    this changes some time stamps for Africa/Ceuta before 1929, which
+    are probably guesswork anyway.  (Thanks to Steve Allen and
+    Pierpaolo Bernardi for the heads-ups, and to Michael Deckers for
+    correcting the 1901 transition.)
+
+    Ecuador observed DST from 1992-11-28 to 1993-02-05.
+    (Thanks to Alois Treindl.)
+
+    Asia/Atyrau and Asia/Oral were at +03 (not +04) before 1930-06-21.
+    (Thanks to Stepan Golosunov.)
+
+  Changes to past and future time zone abbreviations
+
+    Switch to numeric time zone abbreviations for South America, as
+    part of the ongoing project of removing invented abbreviations.
+    This avoids the need to invent an abbreviation for the new Chilean
+    new zone.  Similarly, switch from invented to numeric time zone
+    abbreviations for Afghanistan, American Samoa, the Azores,
+    Bangladesh, Bhutan, the British Indian Ocean Territory, Brunei,
+    Cape Verde, Chatham Is, Christmas I, Cocos (Keeling) Is, Cook Is,
+    Dubai, East Timor, Eucla, Fiji, French Polynesia, Greenland,
+    Indochina, Iran, Iraq, Kiribati, Lord Howe, Macquarie, Malaysia,
+    the Maldives, Marshall Is, Mauritius, Micronesia, Mongolia,
+    Myanmar, Nauru, Nepal, New Caledonia, Niue, Norfolk I, Palau,
+    Papua New Guinea, the Philippines, Pitcairn, Qatar, Réunion, St
+    Pierre & Miquelon, Samoa, Saudi Arabia, Seychelles, Singapore,
+    Solomon Is, Tokelau, Tuvalu, Wake, Vanuatu, Wallis & Futuna, and
+    Xinjiang; for 20-minute daylight saving time in Ghana before 1943;
+    for half-hour daylight saving time in Belize before 1944 and in
+    the Dominican Republic before 1975; and for Canary Islands before
+    1946, for Guinea-Bissau before 1975, for Iceland before 1969, for
+    Indian Summer Time before 1942, for Indonesia before around 1964,
+    for Kenya before 1960, for Liberia before 1973, for Madeira before
+    1967, for Namibia before 1943, for the Netherlands in 1937-9, for
+    Pakistan before 1971, for Western Sahara before 1977, and for
+    Zaporozhye in 1880-1924.
+
+    For Alaska time from 1900 through 1967, instead of "CAT" use the
+    abbreviation "AST", the abbreviation commonly used at the time
+    (Atlantic Standard Time had not been standardized yet).  Use "AWT"
+    and "APT" instead of the invented abbreviations "CAWT" and "CAPT".
+
+    Use "CST" and "CDT" instead of invented abbreviations for Macau
+    before 1999 and Taiwan before 1938, and use "JST" instead of the
+    invented abbreviation "JCST" for Japan and Korea before 1938.
+
+  Change to database entry category
+
+    Move the Pacific/Johnston link from 'australasia' to 'backward',
+    since Johnston is now uninhabited.
+
+  Changes to code
+
+    zic no longer mishandles some transitions in January 2038 when it
+    attempts to work around Qt bug 53071.  This fixes a bug affecting
+    Pacific/Tongatapu that was introduced in zic 2016e.  localtime.c
+    now contains a workaround, useful when loading a file generated by
+    a buggy zic.  (Problem and localtime.c fix reported by Bradley
+    White.)
+
+    zdump -i now outputs non-hour numeric time zone abbreviations
+    without a colon, e.g., "+0530" rather than "+05:30".  This agrees
+    with zic %z and with common practice, and simplifies auditing of
+    zdump output.
+
+    zdump is now buildable again with -DUSE_LTZ=0.
+    (Problem reported by Joseph Myers.)
+
+    zdump.c now always includes private.h, to avoid code duplication
+    with private.h.  (Problem reported by Kees Dekker.)
+
+    localtime.c no longer mishandles early or late timestamps
+    when TZ is set to a POSIX-style string that specifies DST.
+    (Problem reported by Kees Dekker.)
+
+    date and strftime now cause %z to generate "-0000" instead of
+    "+0000" when the UT offset is zero and the time zone abbreviation
+    begins with "-".
+
+  Changes to documentation and commentary
+
+    The 'Theory' file now better documents choice of historical time
+    zone abbreviations.  (Problems reported by Michael Deckers.)
+
+    tz-link.htm now covers leap smearing, which is popular in clouds.
+
+
+Release 2016j - 2016-11-22 23:17:13 -0800
+
+  Briefly: Saratov, Russia moves from +03 to +04 on 2016-12-04.
+
+  Changes to future time stamps
+
+    Saratov, Russia switches from +03 to +04 on 2016-12-04 at 02:00.
+    This hives off a new zone Europe/Saratov from Europe/Volgograd.
+    (Thanks to Yuri Konotopov and Stepan Golosunov.)
+
+  Changes to past time stamps
+
+    The new zone Asia/Atyrau for Atyraū Region, Kazakhstan, is like
+    Asia/Aqtau except it switched from +05/+06 to +04/+05 in spring
+    1999, not fall 1994.  (Thanks to Stepan Golosunov.)
+
+  Changes to past time zone abbreviations
+
+    Asia/Gaza and Asia/Hebron now use "EEST", not "EET", to denote
+    summer time before 1948.  The old use of "EET" was a typo.
+
+  Changes to code
+
+    zic no longer mishandles file systems that lack hard links, fixing
+    bugs introduced in 2016g.  (Problems reported by Tom Lane.)
+    Also, when the destination already contains symbolic links, zic
+    should now work better on systems where the 'link' system call
+    does not follow symbolic links.
+
+  Changes to documentation and commentary
+
+    tz-link.htm now documents the relationship between release version
+    numbers and development-repository commit tags.  (Suggested by
+    Paul Koning.)
+
+    The 'Theory' file now documents UT.
+
+    iso3166.tab now accents "Curaçao", and commentary now mentions
+    the names "Cabo Verde" and "Czechia".  (Thanks to Jiří Boháč.)
+
+
+Release 2016i - 2016-11-01 23:19:52 -0700
+
+  Briefly: Cyprus split into two time zones on 2016-10-30, and Tonga
+  reintroduces DST on 2016-11-06.
+
+  Changes to future time stamps
+
+    Pacific/Tongatapu begins DST on 2016-11-06 at 02:00, ending on
+    2017-01-15 at 03:00.  Assume future observances in Tonga will be
+    from the first Sunday in November through the third Sunday in
+    January, like Fiji.  (Thanks to Pulu ʻAnau.)  Switch to numeric
+    time zone abbreviations for this zone.
+
+  Changes to past and future time stamps
+
+    Northern Cyprus is now +03 year round, causing a split in Cyprus
+    time zones starting 2016-10-30 at 04:00.  This creates a zone
+    Asia/Famagusta.  (Thanks to Even Scharning and Matt Johnson.)
+
+    Antarctica/Casey switched from +08 to +11 on 2016-10-22.
+    (Thanks to Steffen Thorsen.)
+
+  Changes to past time stamps
+
+    Several corrections were made for pre-1975 time stamps in Italy.
+    These affect Europe/Malta, Europe/Rome, Europe/San_Marino, and
+    Europe/Vatican.
+
+    First, the 1893-11-01 00:00 transition in Italy used the new UT
+    offset (+01), not the old (+00:49:56).  (Thanks to Michael
+    Deckers.)
+
+    Second, rules for daylight saving in Italy were changed to agree
+    with Italy's National Institute of Metrological Research (INRiM)
+    except for 1944, as follows (thanks to Pierpaolo Bernardi, Brian
+    Inglis, and Michael Deckers):
+
+      The 1916-06-03 transition was at 24:00, not 00:00.
+
+      The 1916-10-01, 1919-10-05, and 1920-09-19 transitions were at
+      00:00, not 01:00.
+
+      The 1917-09-30 and 1918-10-06 transitions were at 24:00, not
+      01:00.
+
+      The 1944-09-17 transition was at 03:00, not 01:00.  This
+      particular change is taken from Italian law as INRiM's table,
+      (which says 02:00) appears to have a typo here.  Also, keep the
+      1944-04-03 transition for Europe/Rome, as Rome was controlled by
+      Germany then.
+
+      The 1967-1970 and 1972-1974 fallback transitions were at 01:00,
+      not 00:00.
+
+  Changes to code
+
+    The code should now be buildable on AmigaOS merely by setting the
+    appropriate Makefile variables.  (From a patch by Carsten Larsen.)
+
+
+Release 2016h - 2016-10-19 23:17:57 -0700
+
+  Changes to future time stamps
+
+    Asia/Gaza and Asia/Hebron end DST on 2016-10-29 at 01:00, not
+    2016-10-21 at 00:00.  (Thanks to Sharef Mustafa.)  Predict that
+    future fall transitions will be on the last Saturday of October
+    at 01:00, which is consistent with predicted spring transitions
+    on the last Saturday of March.  (Thanks to Tim Parenti.)
+
+  Changes to past time stamps
+
+    In Turkey, transitions in 1986-1990 were at 01:00 standard time
+    not at 02:00, and the spring 1994 transition was on March 20, not
+    March 27.  (Thanks to Kıvanç Yazan.)
+
+  Changes to past and future time zone abbreviations
+
+    Asia/Colombo now uses numeric time zone abbreviations like "+0530"
+    instead of alphabetic ones like "IST" and "LKT".  Various
+    English-language sources use "IST", "LKT" and "SLST", with no
+    working consensus.  (Usage of "SLST" mentioned by Sadika
+    Sumanapala.)
+
+  Changes to code
+
+    zic no longer mishandles relativizing file names when creating
+    symbolic links like /etc/localtime, when these symbolic links
+    are outside the usual directory hierarchy.  This fixes a bug
+    introduced in 2016g.  (Problem reported by Andreas Stieger.)
+
+  Changes to build procedure
+
+    New rules 'traditional_tarballs' and 'traditional_signatures' for
+    building just the traditional-format distribution.  (Requested by
+    Deborah Goldsmith.)
+
+    The file 'version' is now put into the tzdata tarball too.
+    (Requested by Howard Hinnant.)
+
+  Changes to documentation and commentary
+
+    The 'Theory' file now has a section on interface stability.
+    (Requested by Paul Koning.)  It also mentions features like
+    tm_zone and localtime_rz that have long been supported by the
+    reference code.
+
+    tz-link.htm has improved coverage of time zone boundaries suitable
+    for geolocation.  (Thanks to heads-ups from Evan Siroky and Matt
+    Johnson.)
+
+    The US commentary now mentions Allen and the "day of two noons".
+
+    The Fiji commentary mentions the government's 2016-10-03 press
+    release.  (Thanks to Raymond Kumar.)
+
+
+Release 2016g - 2016-09-13 08:56:38 -0700
+
+  Changes to future time stamps
+
+    Turkey switched from EET/EEST (+02/+03) to permanent +03,
+    effective 2016-09-07.  (Thanks to Burak AYDIN.)  Use "+03" rather
+    than an invented abbreviation for the new time.
+
+    New leap second 2016-12-31 23:59:60 UTC as per IERS Bulletin C 52.
+    (Thanks to Tim Parenti.)
+
+  Changes to past time stamps
+
+    For America/Los_Angeles, spring-forward transition times have been
+    corrected from 02:00 to 02:01 in 1948, and from 02:00 to 01:00 in
+    1950-1966.
+
+    For zones using Soviet time on 1919-07-01, transitions to UT-based
+    time were at 00:00 UT, not at 02:00 local time.  The affected
+    zones are Europe/Kirov, Europe/Moscow, Europe/Samara, and
+    Europe/Ulyanovsk.  (Thanks to Alexander Belopolsky.)
+
+  Changes to past and future time zone abbreviations
+
+    The Factory zone now uses the time zone abbreviation -00 instead
+    of a long English-language string, as -00 is now the normal way to
+    represent an undefined time zone.
+
+    Several zones in Antarctica and the former Soviet Union, along
+    with zones intended for ships at sea that cannot use POSIX TZ
+    strings, now use numeric time zone abbreviations instead of
+    invented or obsolete alphanumeric abbreviations.  The affected
+    zones are Antarctica/Casey, Antarctica/Davis,
+    Antarctica/DumontDUrville, Antarctica/Mawson, Antarctica/Rothera,
+    Antarctica/Syowa, Antarctica/Troll, Antarctica/Vostok,
+    Asia/Anadyr, Asia/Ashgabat, Asia/Baku, Asia/Bishkek, Asia/Chita,
+    Asia/Dushanbe, Asia/Irkutsk, Asia/Kamchatka, Asia/Khandyga,
+    Asia/Krasnoyarsk, Asia/Magadan, Asia/Omsk, Asia/Sakhalin,
+    Asia/Samarkand, Asia/Srednekolymsk, Asia/Tashkent, Asia/Tbilisi,
+    Asia/Ust-Nera, Asia/Vladivostok, Asia/Yakutsk, Asia/Yekaterinburg,
+    Asia/Yerevan, Etc/GMT-14, Etc/GMT-13, Etc/GMT-12, Etc/GMT-11,
+    Etc/GMT-10, Etc/GMT-9, Etc/GMT-8, Etc/GMT-7, Etc/GMT-6, Etc/GMT-5,
+    Etc/GMT-4, Etc/GMT-3, Etc/GMT-2, Etc/GMT-1, Etc/GMT+1, Etc/GMT+2,
+    Etc/GMT+3, Etc/GMT+4, Etc/GMT+5, Etc/GMT+6, Etc/GMT+7, Etc/GMT+8,
+    Etc/GMT+9, Etc/GMT+10, Etc/GMT+11, Etc/GMT+12, Europe/Kaliningrad,
+    Europe/Minsk, Europe/Samara, Europe/Volgograd, and
+    Indian/Kerguelen.  For Europe/Moscow the invented abbreviation MSM
+    was replaced by +05, whereas MSK and MSD were kept as they are not
+    our invention and are widely used.
+
+  Changes to zone names
+
+    Rename Asia/Rangoon to Asia/Yangon, with a backward compatibility link.
+    (Thanks to David Massoud.)
+
+  Changes to code
+
+    zic no longer generates binary files containing POSIX TZ-like
+    strings that disagree with the local time type after the last
+    explicit transition in the data.  This fixes a bug with
+    Africa/Casablanca and Africa/El_Aaiun in some year-2037 time
+    stamps on the reference platform.  (Thanks to Alexander Belopolsky
+    for reporting the bug and suggesting a way forward.)
+
+    If the installed localtime and/or posixrules files are symbolic
+    links, zic now keeps them symbolic links when updating them, for
+    compatibility with platforms like OpenSUSE where other programs
+    configure these files as symlinks.
+
+    zic now avoids hard linking to symbolic links, avoids some
+    unnecessary mkdir and stat system calls, and uses shorter file
+    names internally.
+
+    zdump has a new -i option to generate transitions in a
+    more-compact but still human-readable format.  This option is
+    experimental, and the output format may change in future versions.
+    (Thanks to Jon Skeet for suggesting that an option was needed,
+    and thanks to Tim Parenti and Chris Rovick for further comments.)
+
+  Changes to build procedure
+
+    An experimental distribution format is available, in addition
+    to the traditional format which will continue to be distributed.
+    The new format is a tarball tzdb-VERSION.tar.lz with signature
+    file tzdb-VERSION.tar.lz.asc.  It unpacks to a top-level directory
+    tzdb-VERSION containing the code and data of the traditional
+    two-tarball format, along with extra data that may be useful.
+    (Thanks to Antonio Diaz Diaz, Oscar van Vlijmen, and many others
+    for comments about the experimental format.)
+
+    The release version number is now more accurate in the usual case
+    where releases are built from a Git repository.  For example, if
+    23 commits and some working-file changes have been made since
+    release 2016g, the version number is now something like
+    '2016g-23-g50556e3-dirty' instead of the misleading '2016g'.
+    Tagged releases use the same version number format as before,
+    e.g., '2016g'.  To support the more-accurate version number, its
+    specification has moved from a line in the Makefile to a new
+    source file 'version'.
+
+    The experimental distribution contains a file to2050.tzs that
+    contains what should be the output of 'zdump -i -c 2050' on
+    primary zones.  If this file is available, 'make check' now checks
+    that zdump generates this output.
+
+    'make check_web' now works on Fedora-like distributions.
+
+  Changes to documentation and commentary
+
+    tzfile.5 now documents the new restriction on POSIX TZ-like
+    strings that is now implemented by zic.
+
+    Comments now cite URLs for some 1917-1921 Russian DST decrees.
+    (Thanks to Alexander Belopolsky.)
+
+    tz-link.htm mentions JuliaTime (thanks to Curtis Vogt) and Time4J
+    (thanks to Meno Hochschild) and ThreeTen-Extra, and its
+    description of Java 8 has been brought up to date (thanks to
+    Stephen Colebourne).  Its description of local time on Mars has
+    been updated to match current practice, and URLs have been updated
+    and some obsolete ones removed.
+
+
+Release 2016f - 2016-07-05 16:26:51 +0200
+
+  Changes affecting future time stamps
+
+    The Egyptian government changed its mind on short notice, and
+    Africa/Cairo will not introduce DST starting 2016-07-07 after all.
+    (Thanks to Mina Samuel.)
+
+    Asia/Novosibirsk switches from +06 to +07 on 2016-07-24 at 02:00.
+    (Thanks to Stepan Golosunov.)
+
+  Changes to past and future time stamps
+
+    Asia/Novokuznetsk and Asia/Novosibirsk now use numeric time zone
+    abbreviations instead of invented ones.
+
+  Changes affecting past time stamps
+
+    Europe/Minsk's 1992-03-29 spring-forward transition was at 02:00 not 00:00.
+    (Thanks to Stepan Golosunov.)
+
+
+Release 2016e - 2016-06-14 08:46:16 -0700
+
+  Changes affecting future time stamps
+
+    Africa/Cairo observes DST in 2016 from July 7 to the end of October.
+    Guess October 27 and 24:00 transitions.  (Thanks to Steffen Thorsen.)
+    For future years, guess April's last Thursday to October's last
+    Thursday except for Ramadan.
+
+  Changes affecting past time stamps
+
+    Locations while uninhabited now use '-00', not 'zzz', as a
+    placeholder time zone abbreviation.  This is inspired by Internet
+    RFC 3339 and is more consistent with numeric time zone
+    abbreviations already used elsewhere.  The change affects several
+    arctic and antarctic locations, e.g., America/Cambridge_Bay before
+    1920 and Antarctica/Troll before 2005.
+
+    Asia/Baku's 1992-09-27 transition from +04 (DST) to +04 (non-DST) was
+    at 03:00, not 23:00 the previous day.  (Thanks to Michael Deckers.)
+
+  Changes to code
+
+    zic now outputs a dummy transition at time 2**31 - 1 in zones
+    whose POSIX-style TZ strings contain a '<'.  This mostly works
+    around Qt bug 53071 <https://bugreports.qt.io/browse/QTBUG-53071>.
+    (Thanks to Zhanibek Adilbekov for reporting the Qt bug.)
+
+  Changes affecting documentation and commentary
+
+    tz-link.htm says why governments should give plenty of notice for
+    time zone or DST changes, and refers to Matt Johnson's blog post.
+
+    tz-link.htm mentions Tzdata for Elixir.  (Thanks to Matt Johnson.)
+
+
+Release 2016d - 2016-04-17 22:50:29 -0700
+
+  Changes affecting future time stamps
+
+    America/Caracas switches from -0430 to -04 on 2016-05-01 at 02:30.
+    (Thanks to Alexander Krivenyshev for the heads-up.)
+
+    Asia/Magadan switches from +10 to +11 on 2016-04-24 at 02:00.
+    (Thanks to Alexander Krivenyshev and Matt Johnson.)
+
+    New zone Asia/Tomsk, split off from Asia/Novosibirsk.  It covers
+    Tomsk Oblast, Russia, which switches from +06 to +07 on 2016-05-29
+    at 02:00.  (Thanks to Stepan Golosunov.)
+
+  Changes affecting past time stamps
+
+    New zone Europe/Kirov, split off from Europe/Volgograd.  It covers
+    Kirov Oblast, Russia, which switched from +04/+05 to +03/+04 on
+    1989-03-26 at 02:00, roughly a year after Europe/Volgograd made
+    the same change.  (Thanks to Stepan Golosunov.)
+
+    Russia and nearby locations had daylight-saving transitions on
+    1992-03-29 at 02:00 and 1992-09-27 at 03:00, instead of on
+    1992-03-28 at 23:00 and 1992-09-26 at 23:00.  (Thanks to Stepan
+    Golosunov.)
+
+    Many corrections to historical time in Kazakhstan from 1991
+    through 2005.  (Thanks to Stepan Golosunov.)  Replace Kazakhstan's
+    invented time zone abbreviations with numeric abbreviations.
+
+  Changes to commentary
+
+    Mention Internet RFCs 7808 (TZDIST) and 7809 (CalDAV time zone references).
+
+
+Release 2016c - 2016-03-23 00:51:27 -0700
+
+  Changes affecting future time stamps
+
+    Azerbaijan no longer observes DST.  (Thanks to Steffen Thorsen.)
+
+    Chile reverts from permanent to seasonal DST.  (Thanks to Juan
+    Correa for the heads-up, and to Tim Parenti for corrections.)
+    Guess that future transitions are August's and May's second
+    Saturdays at 24:00 mainland time.  Also, call the period from
+    2014-09-07 through 2016-05-14 daylight saving time instead of
+    standard time, as that seems more appropriate now.
+
+  Changes affecting past time stamps
+
+    Europe/Kaliningrad and Europe/Vilnius changed from +03/+04 to
+    +02/+03 on 1989-03-26, not 1991-03-31.  Europe/Volgograd changed
+    from +04/+05 to +03/+04 on 1988-03-27, not 1989-03-26.
+    (Thanks to Stepan Golosunov.)
+
+  Changes to commentary
+
+    Several updates and URLs for historical and proposed Russian changes.
+    (Thanks to Stepan Golosunov, Matt Johnson, and Alexander Krivenyshev.)
+
+
+Release 2016b - 2016-03-12 17:30:14 -0800
+
+  Compatibility note
+
+    Starting with release 2016b, some data entries cause zic implementations
+    derived from tz releases 2005j through 2015e to issue warnings like
+    "time zone abbreviation differs from POSIX standard (+03)".
+    These warnings should not otherwise affect zic's output and can safely be
+    ignored on today's platforms, as the warnings refer to a restriction in
+    POSIX.1-1988 that was removed in POSIX.1-2001.  One way to suppress the
+    warnings is to upgrade to zic derived from tz releases 2015f and later.
+
+  Changes affecting future time stamps
+
+    New zones Europe/Astrakhan and Europe/Ulyanovsk for Astrakhan and
+    Ulyanovsk Oblasts, Russia, both of which will switch from +03 to +04 on
+    2016-03-27 at 02:00 local time.  They need distinct zones since their
+    post-1970 histories disagree.  New zone Asia/Barnaul for Altai Krai and
+    Altai Republic, Russia, which will switch from +06 to +07 on the same date
+    and local time.  The Astrakhan change is already official; the others have
+    passed the first reading in the State Duma and are extremely likely.
+    Also, Asia/Sakhalin moves from +10 to +11 on 2016-03-27 at 02:00.
+    (Thanks to Alexander Krivenyshev for the heads-up, and to Matt Johnson
+    and Stepan Golosunov for followup.)
+
+    As a trial of a new system that needs less information to be made up,
+    the new zones use numeric time zone abbreviations like "+04"
+    instead of invented abbreviations like "ASTT".
+
+    Haiti will not observe DST in 2016.  (Thanks to Jean Antoine via
+    Steffen Thorsen.)
+
+    Palestine's spring-forward transition on 2016-03-26 is at 01:00, not 00:00.
+    (Thanks to Hannah Kreitem.) Guess future transitions will be March's last
+    Saturday at 01:00, not March's last Friday at 24:00.
+
+  Changes affecting past time stamps
+
+    Europe/Chisinau observed DST during 1990, and switched from +04 to
+    +03 at 1990-05-06 02:00, instead of switching from +03 to +02.
+    (Thanks to Stepan Golosunov.)
+
+    1991 abbreviations in Europe/Samara should be SAMT/SAMST, not
+    KUYT/KUYST.  (Thanks to Stepan Golosunov.)
+
+  Changes to code
+
+    tzselect's diagnostics and checking, and checktab.awk's checking,
+    have been improved.  (Thanks to J William Piggott.)
+
+    tzcode now builds under MinGW.  (Thanks to Ian Abbott and Esben Haabendal.)
+
+    tzselect now tests Julian-date TZ settings more accurately.
+    (Thanks to J William Piggott.)
+
+  Changes to commentary
+
+    Comments in zone tables have been improved.  (Thanks to J William Piggott.)
+
+    tzselect again limits its menu comments so that menus fit on a
+    24×80 alphanumeric display.
+
+    A new web page tz-how-to.html.  (Thanks to Bill Seymour.)
+
+    In the Theory file, the description of possible time zone abbreviations in
+    tzdata has been cleaned up, as the old description was unclear and
+    inconsistent.  (Thanks to Alain Mouette for reporting the problem.)
+
+
+Release 2016a - 2016-01-26 23:28:02 -0800
+
+  Changes affecting future time stamps
+
+    America/Cayman will not observe daylight saving this year after all.
+    Revert our guess that it would.  (Thanks to Matt Johnson.)
+
+    Asia/Chita switches from +0800 to +0900 on 2016-03-27 at 02:00.
+    (Thanks to Alexander Krivenyshev.)
+
+    Asia/Tehran now has DST predictions for the year 2038 and later,
+    to be March 21 00:00 to September 21 00:00.  This is likely better
+    than predicting no DST, albeit off by a day every now and then.
+
+  Changes affecting past and future time stamps
+
+    America/Metlakatla switched from PST all year to AKST/AKDT on
+    2015-11-01 at 02:00.  (Thanks to Steffen Thorsen.)
+
+    America/Santa_Isabel has been removed, and replaced with a
+    backward compatibility link to America/Tijuana.  Its contents were
+    apparently based on a misreading of Mexican legislation.
+
+  Changes affecting past time stamps
+
+    Asia/Karachi's two transition times in 2002 were off by a minute.
+    (Thanks to Matt Johnson.)
+
+  Changes affecting build procedure
+
+    An installer can now combine leap seconds with use of the backzone file,
+    e.g., with 'make PACKRATDATA=backzone REDO=posix_right zones'.
+    The old 'make posix_packrat' rule is now marked as obsolescent.
+    (Thanks to Ian Abbott for an initial implementation.)
+
+  Changes affecting documentation and commentary
+
+    A new file LICENSE makes it easier to see that the code and data
+    are mostly public-domain.  (Thanks to James Knight.)  The three
+    non-public-domain files now use the current (3-clause) BSD license
+    instead of older versions of that license.
+
+    tz-link.htm mentions the BDE library (thanks to Andrew Paprocki),
+    CCTZ (thanks to Tim Parenti), TimeJones.com, and has a new section
+    on editing tz source files (with a mention of Sublime zoneinfo,
+    thanks to Gilmore Davidson).
+
+    The Theory and asia files now mention the 2015 book "The Global
+    Transformation of Time, 1870-1950", and cite a couple of reviews.
+
+    The America/Chicago entry now documents the informal use of US
+    central time in Fort Pierre, South Dakota.  (Thanks to Rick
+    McDermid, Matt Johnson, and Steve Jones.)
+
+
+Release 2015g - 2015-10-01 00:39:51 -0700
+
+  Changes affecting future time stamps
+
+    Turkey's 2015 fall-back transition is scheduled for Nov. 8, not Oct. 25.
+    (Thanks to Fatih.)
+
+    Norfolk moves from +1130 to +1100 on 2015-10-04 at 02:00 local time.
+    (Thanks to Alexander Krivenyshev.)
+
+    Fiji's 2016 fall-back transition is scheduled for January 17, not 24.
+    (Thanks to Ken Rylander.)
+
+    Fort Nelson, British Columbia will not fall back on 2015-11-01.  It has
+    effectively been on MST (-0700) since it advanced its clocks on 2015-03-08.
+    New zone America/Fort_Nelson.  (Thanks to Matt Johnson.)
+
+  Changes affecting past time stamps
+
+    Norfolk observed DST from 1974-10-27 02:00 to 1975-03-02 02:00.
+
+  Changes affecting code
+
+    localtime no longer mishandles America/Anchorage after 2037.
+    (Thanks to Bradley White for reporting the bug.)
+
+    On hosts with signed 32-bit time_t, localtime no longer mishandles
+    Pacific/Fiji after 2038-01-16 14:00 UTC.
+
+    The localtime module allows the variables 'timezone', 'daylight',
+    and 'altzone' to be in common storage shared with other modules,
+    and declares them in case the system <time.h> does not.
+    (Problems reported by Kees Dekker.)
+
+    On platforms with tm_zone, strftime.c now assumes it is not NULL.
+    This simplifies the code and is consistent with zdump.c.
+    (Problem reported by Christos Zoulas.)
+
+  Changes affecting documentation
+
+   The tzfile man page now documents that transition times denote the
+   starts (not the ends) of the corresponding time periods.
+   (Ambiguity reported by Bill Seymour.)
+
+
+Release 2015f - 2015-08-10 18:06:56 -0700
+
+  Changes affecting future time stamps
+
+    North Korea switches to +0830 on 2015-08-15.  (Thanks to Steffen Thorsen.)
+    The abbreviation remains "KST".  (Thanks to Robert Elz.)
+
+    Uruguay no longer observes DST.  (Thanks to Steffen Thorsen
+    and Pablo Camargo.)
+
+  Changes affecting past and future time stamps
+
+    Moldova starts and ends DST at 00:00 UTC, not at 01:00 UTC.
+    (Thanks to Roman Tudos.)
+
+  Changes affecting data format and code
+
+    zic's '-y YEARISTYPE' option is no longer documented.  The TYPE
+    field of a Rule line should now be '-'; the old values 'even',
+    'odd', 'uspres', 'nonpres', 'nonuspres' were already undocumented.
+    Although the implementation has not changed, these features do not
+    work in the default installation, they are not used in the data,
+    and they are now considered obsolescent.
+
+    zic now checks that two rules don't take effect at the same time.
+    (Thanks to Jon Skeet and Arthur David Olson.)  Constraints on
+    simultaneity are now documented.
+
+    The two characters '%z' in a zone format now stand for the UT
+    offset, e.g., '-07' for seven hours behind UT and '+0530' for
+    five hours and thirty minutes ahead.  This better supports time
+    zone abbreviations conforming to POSIX.1-2001 and later.
+
+  Changes affecting installed data files
+
+    Comments for America/Halifax and America/Glace_Bay have been improved.
+    (Thanks to Brian Inglis.)
+
+    Data entries have been simplified for Atlantic/Canary, Europe/Simferopol,
+    Europe/Sofia, and Europe/Tallinn.  This yields slightly smaller
+    installed data files for Europe/Simferopol and Europe/Tallinn.
+    It does not affect timestamps.  (Thanks to Howard Hinnant.)
+
+  Changes affecting code
+
+    zdump and zic no longer warn about valid time zone abbreviations
+    like '-05'.
+
+    Some Visual Studio 2013 warnings have been suppressed.
+    (Thanks to Kees Dekker.)
+
+    'date' no longer sets the time of day and its -a, -d, -n and -t
+    options have been removed.  Long obsolescent, the implementation
+    of these features had porting problems.  Builders no longer need
+    to configure HAVE_ADJTIME, HAVE_SETTIMEOFDAY, or HAVE_UTMPX_H.
+    (Thanks to Kees Dekker for pointing out the problem.)
+
+  Changes affecting documentation
+
+    The Theory file mentions naming issues earlier, as these seem to be
+    poorly publicized (thanks to Gilmore Davidson for reporting the problem).
+
+    tz-link.htm mentions Time Zone Database Parser (thanks to Howard Hinnant).
+
+    Mention that Herbert Samuel introduced the term "Summer Time".
+
+
+Release 2015e - 2015-06-13 10:56:02 -0700
+
+  Changes affecting future time stamps
+
+    Morocco will suspend DST from 2015-06-14 03:00 through 2015-07-19 02:00,
+    not 06-13 and 07-18 as we had guessed.  (Thanks to Milamber.)
+
+    Assume Cayman Islands will observe DST starting next year, using US rules.
+    Although it isn't guaranteed, it is the most likely.
+
+  Changes affecting data format
+
+    The file 'iso3166.tab' now uses UTF-8, so that its entries can better
+    spell the names of Åland Islands, Côte d'Ivoire, and Réunion.
+
+  Changes affecting code
+
+    When displaying data, tzselect converts it to the current locale's
+    encoding if the iconv command works.  (Problem reported by random832.)
+
+    tzselect no longer mishandles Dominica, fixing a bug introduced
+    in Release 2014f.  (Problem reported by Owen Leibman.)
+
+    zic -l no longer fails when compiled with -DTZDEFAULT=\"/etc/localtime\".
+    This fixes a bug introduced in Release 2014f.
+    (Problem reported by Leonardo Chiquitto.)
+
+
+Release 2015d - 2015-04-24 08:09:46 -0700
+
+  Changes affecting future time stamps
+
+    Egypt will not observe DST in 2015 and will consider canceling it
+    permanently.  For now, assume no DST indefinitely.
+    (Thanks to Ahmed Nazmy and Tim Parenti.)
+
+  Changes affecting past time stamps
+
+    America/Whitehorse switched from UT -09 to -08 on 1967-05-28, not
+    1966-07-01.  Also, Yukon's time zone history is documented better.
+    (Thanks to Brian Inglis and Dennis Ferguson.)
+
+  Change affecting past and future time zone abbreviations
+
+    The abbreviations for Hawaii-Aleutian standard and daylight times
+    have been changed from HAST/HADT to HST/HDT, as per US Government
+    Printing Office style.  This affects only America/Adak since 1983,
+    as America/Honolulu was already using the new style.
+
+  Changes affecting code
+
+   zic has some minor performance improvements.
+
+
+Release 2015c - 2015-04-11 08:55:55 -0700
+
+  Changes affecting future time stamps
+
+    Egypt's spring-forward transition is at 24:00 on April's last Thursday,
+    not 00:00 on April's last Friday.  2015's transition will therefore be on
+    Thursday, April 30 at 24:00, not Friday, April 24 at 00:00.  Similar fixes
+    apply to 2026, 2037, 2043, etc.  (Thanks to Steffen Thorsen.)
+
+  Changes affecting past time stamps
+
+    The following changes affect some pre-1991 Chile-related time stamps
+    in America/Santiago, Antarctica/Palmer, and Pacific/Easter.
+
+      The 1910 transition was January 10, not January 1.
+
+      The 1918 transition was September 10, not September 1.
+
+      The UT -04 time observed from 1932 to 1942 is now considered to
+      be standard time, not year-round DST.
+
+      Santiago observed DST (UT -03) from 1946-07-15 through
+      1946-08-31, then reverted to standard time, then switched to -05
+      on 1947-04-01.
+
+      Assume transitions before 1968 were at 00:00, since we have no data
+      saying otherwise.
+
+      The spring 1988 transition was 1988-10-09, not 1988-10-02.
+      The fall 1990 transition was 1990-03-11, not 1990-03-18.
+
+      Assume no UT offset change for Pacific/Easter on 1890-01-01,
+      and omit all transitions on Pacific/Easter from 1942 through 1946
+      since we have no data suggesting that they existed.
+
+    One more zone has been turned into a link, as it differed
+    from an existing zone only for older time stamps.  As usual,
+    this change affects UT offsets in pre-1970 time stamps only.
+    The zone's old contents have been moved to the 'backzone' file.
+    The affected zone is America/Montreal.
+
+  Changes affecting commentary
+
+    Mention the TZUpdater tool.
+
+    Mention "The Time Now".  (Thanks to Brandon Ramsey.)
+
+
+Release 2015b - 2015-03-19 23:28:11 -0700
+
+  Changes affecting future time stamps
+
+    Mongolia will start observing DST again this year, from the last
+    Saturday in March at 02:00 to the last Saturday in September at 00:00.
+    (Thanks to Ganbold Tsagaankhuu.)
+
+    Palestine will start DST on March 28, not March 27.  Also,
+    correct the fall 2014 transition from September 26 to October 24.
+    Adjust future predictions accordingly.  (Thanks to Steffen Thorsen.)
+
+  Changes affecting past time stamps
+
+    The 1982 zone shift in Pacific/Easter has been corrected, fixing a 2015a
+    regression.  (Thanks to Stuart Bishop for reporting the problem.)
+
+    Some more zones have been turned into links, when they differed
+    from existing zones only for older time stamps.  As usual,
+    these changes affect UT offsets in pre-1970 time stamps only.
+    Their old contents have been moved to the 'backzone' file.
+    The affected zones are: America/Antigua, America/Cayman,
+    Pacific/Midway, and Pacific/Saipan.
+
+  Changes affecting time zone abbreviations
+
+    Correct the 1992-2010 DST abbreviation in Volgograd from "MSK" to "MSD".
+    (Thanks to Hank W.)
+
+  Changes affecting code
+
+    Fix integer overflow bug in reference 'mktime' implementation.
+    (Problem reported by Jörg Richter.)
+
+    Allow -Dtime_tz=time_t compilations, and allow -Dtime_tz=... libraries
+    to be used in the same executable as standard-library time_t functions.
+    (Problems reported by Bradley White.)
+
+  Changes affecting commentary
+
+    Cite the recent Mexican decree changing Quintana Roo's time zone.
+    (Thanks to Carlos Raúl Perasso.)
+
+    Likewise for the recent Chilean decree.  (Thanks to Eduardo Romero Urra.)
+
+    Update info about Mars time.
+
+
+Release 2015a - 2015-01-29 22:35:20 -0800
+
+  Changes affecting future time stamps
+
+    The Mexican state of Quintana Roo, represented by America/Cancun,
+    will shift from Central Time with DST to Eastern Time without DST
+    on 2015-02-01 at 02:00.  (Thanks to Steffen Thorsen and Gwillim Law.)
+
+    Chile will not change clocks in April or thereafter; its new standard time
+    will be its old daylight saving time.  This affects America/Santiago,
+    Pacific/Easter, and Antarctica/Palmer.  (Thanks to Juan Correa.)
+
+    New leap second 2015-06-30 23:59:60 UTC as per IERS Bulletin C 49.
+    (Thanks to Tim Parenti.)
+
+  Changes affecting past time stamps
+
+    Iceland observed DST in 1919 and 1921, and its 1939 fallback
+    transition was Oct. 29, not Nov. 29.  Remove incorrect data from
+    Shanks about time in Iceland between 1837 and 1908.
+
+    Some more zones have been turned into links, when they differed
+    from existing zones only for older time stamps.  As usual,
+    these changes affect UT offsets in pre-1970 time stamps only.
+    Their old contents have been moved to the 'backzone' file.
+    The affected zones are: Asia/Aden, Asia/Bahrain, Asia/Kuwait,
+    and Asia/Muscat.
+
+  Changes affecting code
+
+    tzalloc now scrubs time zone abbreviations compatibly with the way
+    that tzset always has, by replacing invalid bytes with '_' and by
+    shortening too-long abbreviations.
+
+    tzselect ports to POSIX awk implementations, no longer mishandles
+    POSIX TZ settings when GNU awk is used, and reports POSIX TZ
+    settings to the user.  (Thanks to Stefan Kuhn.)
+
+  Changes affecting build procedure
+
+    'make check' now checks for links to links in the data.
+    One such link (for Africa/Asmera) has been fixed.
+    (Thanks to Stephen Colebourne for pointing out the problem.)
+
+  Changes affecting commentary
+
+    The leapseconds file commentary now mentions the expiration date.
+    (Problem reported by Martin Burnicki.)
+
+    Update Mexican Library of Congress URL.
+
+
+Release 2014j - 2014-11-10 17:37:11 -0800
+
+  Changes affecting current and future time stamps
+
+    Turks & Caicos' switch from US eastern time to UT -04 year-round
+    did not occur on 2014-11-02 at 02:00.  It's currently scheduled
+    for 2015-11-01 at 02:00.  (Thanks to Chris Walton.)
+
+  Changes affecting past time stamps
+
+    Many pre-1989 time stamps have been corrected for Asia/Seoul and
+    Asia/Pyongyang, based on sources for the Korean-language Wikipedia
+    entry for time in Korea.  (Thanks to Sanghyuk Jung.)  Also, no
+    longer guess that Pyongyang mimicked Seoul time after World War II,
+    as this is politically implausible.
+
+    Some more zones have been turned into links, when they differed
+    from existing zones only for older time stamps.  As usual,
+    these changes affect UT offsets in pre-1970 time stamps only.
+    Their old contents have been moved to the 'backzone' file.
+    The affected zones are: Africa/Addis_Ababa, Africa/Asmara,
+    Africa/Dar_es_Salaam, Africa/Djibouti, Africa/Kampala,
+    Africa/Mogadishu, Indian/Antananarivo, Indian/Comoro, and
+    Indian/Mayotte.
+
+  Changes affecting commentary
+
+    The commentary is less enthusiastic about Shanks as a source,
+    and is more careful to distinguish UT from UTC.
+
+
+Release 2014i - 2014-10-21 22:04:57 -0700
+
+  Changes affecting future time stamps
+
+    Pacific/Fiji will observe DST from 2014-11-02 02:00 to 2015-01-18 03:00.
+    (Thanks to Ken Rylander for the heads-up.)  Guess that future
+    years will use a similar pattern.
+
+    A new Zone Pacific/Bougainville, for the part of Papua New Guinea
+    that plans to switch from UT +10 to +11 on 2014-12-28 at 02:00.
+    (Thanks to Kiley Walbom for the heads-up.)
+
+  Changes affecting time zone abbreviations
+
+    Since Belarus is not changing its clocks even though Moscow is,
+    the time zone abbreviation in Europe/Minsk is changing from FET
+    to its more-traditional value MSK on 2014-10-26 at 01:00.
+    (Thanks to Alexander Bokovoy for the heads-up about Belarus.)
+
+    The new abbreviation IDT stands for the pre-1976 use of UT +08 in
+    Indochina, to distinguish it better from ICT (+07).
+
+  Changes affecting past time stamps
+
+    Many time stamps have been corrected for Asia/Ho_Chi_Minh before 1976
+    (thanks to Trần Ngọc Quân for an indirect pointer to Trần Tiến Bình's
+    authoritative book).  Asia/Ho_Chi_Minh has been added to
+    zone1970.tab, to give tzselect users in Vietnam two choices,
+    since north and south Vietnam disagreed after our 1970 cutoff.
+
+    Asia/Phnom_Penh and Asia/Vientiane have been turned into links, as
+    they differed from existing zones only for older time stamps.  As
+    usual, these changes affect pre-1970 time stamps only.  Their old
+    contents have been moved to the 'backzone' file.
+
+  Changes affecting code
+
+    The time-related library functions now set errno on failure, and
+    some crashes in the new tzalloc-related library functions have
+    been fixed.  (Thanks to Christos Zoulas for reporting most of
+    these problems and for suggesting fixes.)
+
+    If USG_COMPAT is defined and the requested timestamp is standard time,
+    the tz library's localtime and mktime functions now set the extern
+    variable timezone to a value appropriate for that timestamp; and
+    similarly for ALTZONE, daylight saving time, and the altzone variable.
+    This change is a companion to the tzname change in 2014h, and is
+    designed to make timezone and altzone more compatible with tzname.
+
+    The tz library's functions now set errno to EOVERFLOW if they fail
+    because the result cannot be represented.  ctime and ctime_r now
+    return NULL and set errno when a timestamp is out of range, rather
+    than having undefined behavior.
+
+    Some bugs associated with the new 2014g functions have been fixed.
+    This includes a bug that largely incapacitated the new functions
+    time2posix_z and posix2time_z.  (Thanks to Christos Zoulas.)
+    It also includes some uses of uninitialized variables after tzalloc.
+    The new code uses the standard type 'ssize_t', which the Makefile
+    now gives porting advice about.
+
+  Changes affecting commentary
+
+    Updated URLs for NRC Canada (thanks to Matt Johnson and Brian Inglis).
+
+
+Release 2014h - 2014-09-25 18:59:03 -0700
+
+  Changes affecting past timestamps
+
+    America/Jamaica's 1974 spring-forward transition was Jan. 6, not Apr. 28.
+
+    Shanks says Asia/Novokuznetsk switched from LMT (not "NMT") on 1924-05-01,
+    not 1920-01-06.  The old entry was based on a misinterpretation of Shanks.
+
+    Some more zones have been turned into links, when they differed
+    from existing zones only for older timestamps.  As usual,
+    these changes affect UT offsets in pre-1970 timestamps only.
+    Their old contents have been moved to the 'backzone' file.
+    The affected zones are: Africa/Blantyre, Africa/Bujumbura,
+    Africa/Gaborone, Africa/Harare, Africa/Kigali, Africa/Lubumbashi,
+    Africa/Lusaka, Africa/Maseru, and Africa/Mbabane.
+
+  Changes affecting code
+
+    zdump -V and -v now output gmtoff= values on all platforms,
+    not merely on platforms defining TM_GMTOFF.
+
+    The tz library's localtime and mktime functions now set tzname to a value
+    appropriate for the requested timestamp, and zdump now uses this
+    on platforms not defining TM_ZONE, fixing a 2014g regression.
+    (Thanks to Tim Parenti for reporting the problem.)
+
+    The tz library no longer sets tzname if localtime or mktime fails.
+
+    zdump -c no longer mishandles transitions near year boundaries.
+    (Thanks to Tim Parenti for reporting the problem.)
+
+    An access to uninitialized data has been fixed.
+    (Thanks to Jörg Richter for reporting the problem.)
+
+    When THREAD_SAFE is defined, the code ports to the C11 memory model.
+    A memory leak has been fixed if ALL_STATE and THREAD_SAFE are defined
+    and two threads race to initialize data used by gmtime-like functions.
+    (Thanks to Andy Heninger for reporting the problems.)
+
+  Changes affecting build procedure
+
+    'make check' now checks better for properly-sorted data.
+
+  Changes affecting documentation and commentary
+
+    zdump's gmtoff=N output is now documented, and its isdst=D output
+    is now documented to possibly output D values other than 0 or 1.
+
+    zdump -c's treatment of years is now documented to use the
+    Gregorian calendar and Universal Time without leap seconds,
+    and its behavior at cutoff boundaries is now documented better.
+    (Thanks to Arthur David Olson and Tim Parenti for reporting the problems.)
+
+    Programs are now documented to use the proleptic Gregorian calendar.
+    (Thanks to Alan Barrett for the suggestion.)
+
+    Fractional-second GMT offsets have been documented for civil time
+    in 19th-century Chennai, Jakarta, and New York.
+
+
+Release 2014g - 2014-08-28 12:31:23 -0700
+
+  Changes affecting future timestamps
+
+    Turks & Caicos is switching from US eastern time to UT -04
+    year-round, modeled as a switch on 2014-11-02 at 02:00.
+    [As noted in 2014j, this switch was later delayed.]
+
+  Changes affecting past timestamps
+
+    Time in Russia or the USSR before 1926 or so has been corrected by
+    a few seconds in the following zones: Asia/Irkutsk,
+    Asia/Krasnoyarsk, Asia/Omsk, Asia/Samarkand, Asia/Tbilisi,
+    Asia/Vladivostok, Asia/Yakutsk, Europe/Riga, Europe/Samara.  For
+    Asia/Yekaterinburg the correction is a few minutes.  (Thanks to
+    Vladimir Karpinsky.)
+
+    The Portuguese decree of 1911-05-26 took effect on 1912-01-01.
+    This affects 1911 timestamps in Africa/Bissau, Africa/Luanda,
+    Atlantic/Azores, and Atlantic/Madeira.  Also, Lisbon's pre-1912
+    GMT offset was -0:36:45 (rounded from -0:36:44.68), not -0:36:32.
+    (Thanks to Stephen Colebourne for pointing to the decree.)
+
+    Asia/Dhaka ended DST on 2009-12-31 at 24:00, not 23:59.
+
+    A new file 'backzone' contains data which may appeal to
+    connoisseurs of old timestamps, although it is out of scope for
+    the tz database, is often poorly sourced, and contains some data
+    that is known to be incorrect.  The new file is not recommended
+    for ordinary use and its entries are not installed by default.
+    (Thanks to Lester Caine for the high-quality Jersey, Guernsey, and
+    Isle of Man entries.)
+
+    Some more zones have been turned into links, when they differed
+    from existing zones only for older timestamps.  As usual,
+    these changes affect UT offsets in pre-1970 timestamps only.
+    Their old contents have been moved to the 'backzone' file.
+    The affected zones are: Africa/Bangui, Africa/Brazzaville,
+    Africa/Douala, Africa/Kinshasa, Africa/Libreville, Africa/Luanda,
+    Africa/Malabo, Africa/Niamey, and Africa/Porto-Novo.
+
+  Changes affecting code
+
+    Unless NETBSD_INSPIRED is defined to 0, the tz library now
+    supplies functions for creating and using objects that represent
+    time zones. The new functions are tzalloc, tzfree, localtime_rz,
+    mktime_z, and (if STD_INSPIRED is also defined) posix2time_z and
+    time2posix_z.  They are intended for performance: for example,
+    localtime_rz (unlike localtime_r) is trivially thread-safe without
+    locking.  (Thanks to Christos Zoulas for proposing NetBSD-inspired
+    functions, and to Alan Barrett and Jonathan Lennox for helping to
+    debug the change.)
+
+    zdump now builds with the tz library unless USE_LTZ is defined to 0,
+    This lets zdump use tz features even if the system library lacks them.
+    To build zdump with the system library, use 'make CFLAGS=-DUSE_LTZ=0
+    TZDOBJS=zdump.o CHECK_TIME_T_ALTERNATIVES='.
+
+    zdump now uses localtime_rz if available, as it's significantly faster,
+    and it can help zdump better diagnose invalid time zone names.
+    Define HAVE_LOCALTIME_RZ to 0 to suppress this.  HAVE_LOCALTIME_RZ
+    defaults to 1 if NETBSD_INSPIRED && USE_LTZ.  When localtime_rz is
+    not available, zdump now uses localtime_r and tzset if available,
+    as this is a bit cleaner and faster than plain localtime.  Compile
+    with -DHAVE_LOCALTIME_R=0 and/or -DHAVE_TZSET=0 if your system
+    lacks these two functions.
+
+    If THREAD_SAFE is defined to 1, the tz library is now thread-safe.
+    Although not needed for tz's own applications, which are single-threaded,
+    this supports POSIX better if the tz library is used in multithreaded apps.
+
+    Some crashes have been fixed when zdump or the tz library is given
+    invalid or outlandish input.
+
+    The tz library no longer mishandles leap seconds on platforms with
+    unsigned time_t in time zones that lack ordinary transitions after 1970.
+
+    The tz code now attempts to infer TM_GMTOFF and TM_ZONE if not
+    already defined, to make it easier to configure on common platforms.
+    Define NO_TM_GMTOFF and NO_TM_ZONE to suppress this.
+
+    Unless the new macro UNINIT_TRAP is defined to 1, the tz code now
+    assumes that reading uninitialized memory yields garbage values
+    but does not cause other problems such as traps.
+
+    If TM_GMTOFF is defined and UNINIT_TRAP is 0, mktime is now
+    more likely to guess right for ambiguous timestamps near
+    transitions where tm_isdst does not change.
+
+    If HAVE_STRFTIME_L is defined to 1, the tz library now defines
+    strftime_l for compatibility with recent versions of POSIX.
+    Only the C locale is supported, though.  HAVE_STRFTIME_L defaults
+    to 1 on recent POSIX versions, and to 0 otherwise.
+
+    tzselect -c now uses a hybrid distance measure that works better
+    in Africa.  (Thanks to Alan Barrett for noting the problem.)
+
+    The C source code now ports to NetBSD when GCC_DEBUG_FLAGS is used,
+    or when time_tz is defined.
+
+    When HAVE_UTMPX_H is set the 'date' command now builds on systems
+    whose <utmpx.h> file does not define WTMPX_FILE, and when setting
+    the date it updates the wtmpx file if _PATH_WTMPX is defined.
+    This affects GNU/Linux and similar systems.
+
+    For easier maintenance later, some C code has been simplified,
+    some lint has been removed, and the code has been tweaked so that
+    plain 'make' is more likely to work.
+
+    The C type 'bool' is now used for boolean values, instead of 'int'.
+
+    The long-obsolete LOCALE_HOME code has been removed.
+
+    The long-obsolete 'gtime' function has been removed.
+
+  Changes affecting build procedure
+
+    'zdump' no longer links in ialloc.o, as it's not needed.
+
+    'make check_time_t_alternatives' no longer assumes GNU diff.
+
+  Changes affecting distribution tarballs
+
+    The files checktab.awk and zoneinfo2tdf.pl are now distributed in
+    the tzdata tarball instead of the tzcode tarball, since they help
+    maintain the data.  The NEWS and Theory files are now also
+    distributed in the tzdata tarball, as they're relevant for data.
+    (Thanks to Alan Barrett for pointing this out.)  Also, the
+    leapseconds.awk file is no longer distributed in the tzcode
+    tarball, since it belongs in the tzdata tarball (where 2014f
+    inadvertently also distributed it).
+
+  Changes affecting documentation and commentary
+
+    A new file CONTRIBUTING is distributed.  (Thanks to Tim Parenti for
+    suggesting a CONTRIBUTING file, and to Tony Finch and Walter Harms
+    for debugging it.)
+
+    The man pages have been updated to use function prototypes,
+    to document thread-safe variants like localtime_r, and to document
+    the NetBSD-inspired functions tzalloc, tzfree, localtime_rz, and
+    mktime_z.
+
+    The fields in Link lines have been renamed to be more descriptive
+    and more like the parameters of 'ln'.  LINK-FROM has become TARGET,
+    and LINK-TO has become LINK-NAME.
+
+    tz-link.htm mentions the IETF's tzdist working group; Windows
+    Runtime etc. (thanks to Matt Johnson); and HP-UX's tztab.
+
+    Some broken URLs have been fixed in the commentary.  (Thanks to
+    Lester Caine.)
+
+    Commentary about Philippines DST has been updated, and commentary
+    on pre-1970 time in India has been added.
+
+
+Release 2014f - 2014-08-05 17:42:36 -0700
+
+  Changes affecting future timestamps
+
+    Russia will subtract an hour from most of its time zones on 2014-10-26
+    at 02:00 local time.  (Thanks to Alexander Krivenyshev.)
+    There are a few exceptions: Magadan Oblast (Asia/Magadan) and Zabaykalsky
+    Krai are subtracting two hours; conversely, Chukotka Autonomous Okrug
+    (Asia/Anadyr), Kamchatka Krai (Asia/Kamchatka), Kemerovo Oblast
+    (Asia/Novokuznetsk), and the Samara Oblast and the Udmurt Republic
+    (Europe/Samara) are not changing their clocks.  The changed zones are
+    Europe/Kaliningrad, Europe/Moscow, Europe/Simferopol, Europe/Volgograd,
+    Asia/Yekaterinburg, Asia/Omsk, Asia/Novosibirsk, Asia/Krasnoyarsk,
+    Asia/Irkutsk, Asia/Yakutsk, Asia/Vladivostok, Asia/Khandyga,
+    Asia/Sakhalin, and Asia/Ust-Nera; Asia/Magadan will have two hours
+    subtracted; and Asia/Novokuznetsk's time zone abbreviation is affected,
+    but not its UTC offset.  Two zones are added: Asia/Chita (split
+    from Asia/Yakutsk, and also with two hours subtracted) and
+    Asia/Srednekolymsk (split from Asia/Magadan, but with only one hour
+    subtracted).  (Thanks to Tim Parenti for much of the above.)
+
+  Changes affecting time zone abbreviations
+
+    Australian eastern time zone abbreviations are now AEST/AEDT not EST,
+    and similarly for the other Australian zones.  That is, for eastern
+    standard and daylight saving time the abbreviations are AEST and AEDT
+    instead of the former EST for both; similarly, ACST/ACDT, ACWST/ACWDT,
+    and AWST/AWDT are now used instead of the former CST, CWST, and WST.
+    This change does not affect UT offsets, only time zone abbreviations.
+    (Thanks to Rich Tibbett and many others.)
+
+    Asia/Novokuznetsk shifts from NOVT to KRAT (remaining on UT +07)
+    effective 2014-10-26 at 02:00 local time.
+
+    The time zone abbreviation for Xinjiang Time (observed in Ürümqi)
+    has been changed from URUT to XJT.  (Thanks to Luther Ma.)
+
+    Prefer MSK/MSD for Moscow time in Russia, even in other cities.
+    Similarly, prefer EET/EEST for eastern European time in Russia.
+
+    Change time zone abbreviations in (western) Samoa to use "ST" and
+    "DT" suffixes, as this is more likely to match common practice.
+    Prefix "W" to (western) Samoa time when its standard-time offset
+    disagrees with that of American Samoa.
+
+    America/Metlakatla now uses PST, not MeST, to abbreviate its time zone.
+
+    Time zone abbreviations have been updated for Japan's two time
+    zones used 1896-1937.  JWST now stands for Western Standard
+    Time, and JCST for Central Standard Time (formerly this was CJT).
+    These abbreviations are now used for time in Korea, Taiwan,
+    and Sakhalin while controlled by Japan.
+
+  Changes affecting past timestamps
+
+    China's five zones have been simplified to two, since the post-1970
+    differences in the other three seem to have been imaginary.  The
+    zones Asia/Harbin, Asia/Chongqing, and Asia/Kashgar have been
+    removed; backwards-compatibility links still work, albeit with
+    different behaviors for timestamps before May 1980.  Asia/Urumqi's
+    1980 transition to UT +08 has been removed, so that it is now at
+    +06 and not +08.  (Thanks to Luther Ma and to Alois Treindl;
+    Treindl sent helpful translations of two papers by Guo Qingsheng.)
+
+    Some zones have been turned into links, when they differed from existing
+    zones only for older UT offsets where data entries were likely invented.
+    These changes affect UT offsets in pre-1970 timestamps only.  This is
+    similar to the change in release 2013e, except this time for western
+    Africa.  The affected zones are: Africa/Bamako, Africa/Banjul,
+    Africa/Conakry, Africa/Dakar, Africa/Freetown, Africa/Lome,
+    Africa/Nouakchott, Africa/Ouagadougou, Africa/Sao_Tome, and
+    Atlantic/St_Helena.  This also affects the backwards-compatibility
+    link Africa/Timbuktu.  (Thanks to Alan Barrett, Stephen Colebourne,
+    Tim Parenti, and David Patte for reporting problems in earlier
+    versions of this change.)
+
+    Asia/Shanghai's pre-standard-time UT offset has been changed from
+    8:05:57 to 8:05:43, the location of Xujiahui Observatory.  Its
+    transition to standard time has been changed from 1928 to 1901.
+
+    Asia/Taipei switched to JWST on 1896-01-01, then to JST on 1937-10-01,
+    then to CST on 1945-09-21 at 01:00, and did not observe DST in 1945.
+    In 1946 it observed DST from 05-15 through 09-30; in 1947
+    from 04-15 through 10-31; and in 1979 from 07-01 through 09-30.
+    (Thanks to Yu-Cheng Chuang.)
+
+    Asia/Riyadh's transition to standard time is now 1947-03-14, not 1950.
+
+    Europe/Helsinki's 1942 fall-back transition was 10-04 at 01:00, not
+    10-03 at 00:00.  (Thanks to Konstantin Hyppönen.)
+
+    Pacific/Pago_Pago has been changed from UT -11:30 to -11 for the
+    period from 1911 to 1950.
+
+    Pacific/Chatham has been changed to New Zealand standard time plus
+    45 minutes for the period before 1957, reflecting a 1956 remark in
+    the New Zealand parliament.
+
+    Europe/Budapest has several pre-1946 corrections: in 1918 the transition
+    out of DST was on 09-16, not 09-29; in 1919 it was on 11-24, not 09-15; in
+    1945 it was on 11-01, not 11-03; in 1941 the transition to DST was 04-08
+    not 04-06 at 02:00; and there was no DST in 1920.
+
+    Africa/Accra is now assumed to have observed DST from 1920 through 1935.
+
+    Time in Russia before 1927 or so has been corrected by a few seconds in
+    the following zones: Europe/Moscow, Asia/Irkutsk, Asia/Tbilisi,
+    Asia/Tashkent, Asia/Vladivostok, Asia/Yekaterinburg, Europe/Helsinki, and
+    Europe/Riga.  Also, Moscow's location has been changed to its Kilometer 0
+    point.  (Thanks to Vladimir Karpinsky for the Moscow changes.)
+
+  Changes affecting data format
+
+    A new file 'zone1970.tab' supersedes 'zone.tab' in the installed data.
+    The new file's extended format allows multiple country codes per zone.
+    The older file is still installed but is deprecated; its format is
+    not changing and it will still be distributed for a while, but new
+    applications should use the new file.
+
+    The new file format simplifies maintenance of obscure locations.
+    To test this, it adds coverage for the Crozet Islands and the
+    Scattered Islands.  (Thanks to Tobias Conradi and Antoine Leca.)
+
+    The file 'iso3166.tab' is planned to switch from ASCII to UTF-8.
+    It is still ASCII now, but commentary about the switch has been added.
+    The new file 'zone1970.tab' already uses UTF-8.
+
+  Changes affecting code
+
+    'localtime', 'mktime', etc. now use much less stack space if ALL_STATE
+    is defined.  (Thanks to Elliott Hughes for reporting the problem.)
+
+    'zic' no longer mishandles input when ignoring case in locales that
+    are not compatible with English, e.g., unibyte Turkish locales when
+    compiled with HAVE_GETTEXT.
+
+    Error diagnostics of 'zic' and 'yearistype' have been reworded so that
+    they no longer use ASCII '-' as if it were a dash.
+
+    'zic' now rejects output file names that contain '.' or '..' components.
+    (Thanks to Tim Parenti for reporting the problem.)
+
+    'zic -v' now warns about output file names that do not follow
+    POSIX rules, or that contain a digit or '.'.  (Thanks to Arthur
+    David Olson for starting the ball rolling on this.)
+
+    Some lint has been removed when using GCC_DEBUG_FLAGS with GCC 4.9.0.
+
+  Changes affecting build procedure
+
+    'zic' no longer links in localtime.o and asctime.o, as they're not needed.
+    (Thanks to John Cochran.)
+
+  Changes affecting documentation and commentary
+
+    The 'Theory' file documents legacy names, the longstanding
+    exceptions to the POSIX-inspired file name rules.
+
+    The 'zic' documentation clarifies the role of time types when
+    interpreting dates.  (Thanks to Arthur David Olson.)
+
+    Documentation and commentary now prefer UTF-8 to US-ASCII,
+    allowing the use of proper accents in foreign words and names.
+    Code and data have not changed because of this.  (Thanks to
+    Garrett Wollman, Ian Abbott, and Guy Harris for helping to debug
+    this.)
+
+    Non-HTML documentation and commentary now use plain-text URLs instead of
+    HTML insertions, and are more consistent about bracketing URLs when they
+    are not already surrounded by white space.  (Thanks to suggestions by
+    Steffen Nurpmeso.)
+
+    There is new commentary about Xujiahui Observatory, the five time-zone
+    project in China from 1918 to 1949, timekeeping in Japanese-occupied
+    Shanghai, and Tibet Time in the 1950s.  The sharp-eyed can spot the
+    warlord Jin Shuren in the data.
+
+    Commentary about the coverage of each Russian zone has been standardized.
+    (Thanks to Tim Parenti).
+
+    There is new commentary about contemporary timekeeping in Ethiopia.
+
+    Obsolete comments about a 2007 proposal for DST in Kuwait has been removed.
+
+    There is new commentary about time in Poland in 1919.
+
+    Proper credit has been given to DST inventor George Vernon Hudson.
+
+    Commentary about time in Metlakatla, AK and Resolute, NU has been
+    improved, with a new source for the former.
+
+    In zone.tab, Pacific/Easter no longer mentions Salas y Gómez, as it
+    is uninhabited.
+
+    Commentary about permanent Antarctic bases has been updated.
+
+    Several typos have been corrected.  (Thanks to Tim Parenti for
+    contributing some of these fixes.)
+
+    tz-link.htm now mentions the JavaScript libraries Moment Timezone,
+    TimezoneJS.Date, Walltime-js, and Timezone.  (Thanks to a heads-up
+    from Matt Johnson.)  Also, it mentions the Go 'latlong' package.
+    (Thanks to a heads-up from Dirkjan Ochtman.)
+
+    The files usno1988, usno1989, usno1989a, usno1995, usno1997, and usno1998
+    have been removed.  These obsolescent US Naval Observatory entries were no
+    longer helpful for maintenance.  (Thanks to Tim Parenti for the suggestion.)
+
+
+Release 2014e - 2014-06-12 21:53:52 -0700
+
+  Changes affecting near-future timestamps
+
+    Egypt's 2014 Ramadan-based transitions are June 26 and July 31 at 24:00.
+    (Thanks to Imed Chihi.)  Guess that from 2015 on Egypt will temporarily
+    switch to standard time at 24:00 the last Thursday before Ramadan, and
+    back to DST at 00:00 the first Friday after Ramadan.
+
+    Similarly, Morocco's are June 28 at 03:00 and August 2 at 02:00.  (Thanks
+    to Milamber Space Network.)  Guess that from 2015 on Morocco will
+    temporarily switch to standard time at 03:00 the last Saturday before
+    Ramadan, and back to DST at 02:00 the first Saturday after Ramadan.
+
+  Changes affecting past timestamps
+
+    The abbreviation "MSM" (Moscow Midsummer Time) is now used instead of
+    "MSD" for Moscow's double daylight time in summer 1921.  Also, a typo
+    "VLASST" has been repaired to be "VLAST" for Vladivostok summer time
+    in 1991.  (Thanks to Hank W. for reporting the problems.)
+
+  Changes affecting commentary
+
+    tz-link.htm now cites RFC 7265 for jCal, mentions PTP and the
+    draft CalDAV extension, updates URLs for TSP, TZInfo, IATA, and
+    removes stale pointers to World Time Explorer and WORLDTIME.
+
+
+Release 2014d - 2014-05-27 21:34:40 -0700
+
+  Changes affecting code
+
+    zic no longer generates files containing timestamps before the Big Bang.
+    This works around GNOME bug 730332
+    <https://bugzilla.gnome.org/show_bug.cgi?id=730332>.
+    (Thanks to Leonardo Chiquitto for reporting the bug, and to
+    Arthur David Olson and James Cloos for suggesting improvements to the fix.)
+
+  Changes affecting documentation
+
+    tz-link.htm now mentions GNOME.
+
+
+Release 2014c - 2014-05-13 07:44:13 -0700
+
+  Changes affecting near-future timestamps
+
+    Egypt observes DST starting 2014-05-15 at 24:00.
+    (Thanks to Ahmad El-Dardiry and Gunther Vermier.)
+    Details have not been announced, except that DST will not be observed
+    during Ramadan.  Guess that DST will stop during the same Ramadan dates as
+    Morocco, and that Egypt's future spring and fall transitions will be the
+    same as 2010 when it last observed DST, namely April's last Friday at
+    00:00 to September's last Thursday at 23:00 standard time.  Also, guess
+    that Ramadan transitions will be at 00:00 standard time.
+
+  Changes affecting code
+
+    zic now generates transitions for minimum time values, eliminating guesswork
+    when handling low-valued timestamps.  (Thanks to Arthur David Olson.)
+
+    Port to Cygwin sans glibc.  (Thanks to Arthur David Olson.)
+
+  Changes affecting commentary and documentation
+
+    Remove now-confusing comment about Jordan.  (Thanks to Oleksii Nochovnyi.)
+
+
+Release 2014b - 2014-03-24 21:28:50 -0700
+
+  Changes affecting near-future timestamps
+
+    Crimea switches to Moscow time on 2014-03-30 at 02:00 local time.
+    (Thanks to Alexander Krivenyshev.)  Move its zone.tab entry from UA to RU.
+
+    New entry for Troll station, Antarctica.  (Thanks to Paul-Inge Flakstad and
+    Bengt-Inge Larsson.)  This is currently an approximation; a better version
+    will require the zic and localtime fixes mentioned below, and the plan is
+    to wait for a while until at least the zic fixes propagate.
+
+  Changes affecting code
+
+    'zic' and 'localtime' no longer reject locations needing four transitions
+    per year for the foreseeable future.  (Thanks to Andrew Main (Zefram).)
+    Also, 'zic' avoids some unlikely failures due to integer overflow.
+
+  Changes affecting build procedure
+
+    'make check' now detects Rule lines defined but never used.
+    The NZAQ rules, an instance of this problem, have been removed.
+
+  Changes affecting commentary and documentation
+
+    Fix Tuesday/Thursday typo in description of time in Israel.
+    (Thanks to Bert Katz via Pavel Kharitonov and Mike Frysinger.)
+
+    Microsoft Windows 8.1 doesn't support tz database names.  (Thanks
+    to Donald MacQueen.)  Instead, the Microsoft Windows Store app
+    library supports them.
+
+    Add comments about Johnston Island time in the 1960s.
+    (Thanks to Lyle McElhaney.)
+
+    Morocco's 2014 DST start will be as predicted.
+    (Thanks to Sebastien Willemijns.)
+
+
+Release 2014a - 2014-03-07 23:30:29 -0800
+
+  Changes affecting near-future timestamps
+
+    Turkey begins DST on 2014-03-31, not 03-30.  (Thanks to Faruk Pasin for
+    the heads-up, and to Tim Parenti for simplifying the update.)
+
+  Changes affecting past timestamps
+
+    Fiji ended DST on 2014-01-19 at 02:00, not the previously-scheduled 03:00.
+    (Thanks to Steffen Thorsen.)
+
+    Ukraine switched from Moscow to Eastern European time on 1990-07-01
+    (not 1992-01-01), and observed DST during the entire next winter.
+    (Thanks to Vladimir in Moscow via Alois Treindl.)
+
+    In 1988 Israel observed DST from 04-10 to 09-04, not 04-09 to 09-03.
+    (Thanks to Avigdor Finkelstein.)
+
+  Changes affecting code
+
+    A uninitialized-storage bug in 'localtime' has been fixed.
+    (Thanks to Logan Chien.)
+
+  Changes affecting the build procedure
+
+    The settings for 'make check_web' now default to Ubuntu 13.10.
+
+  Changes affecting commentary and documentation
+
+    The boundary of the US Pacific time zone is given more accurately.
+    (Thanks to Alan Mintz.)
+
+    Chile's 2014 DST will be as predicted.  (Thanks to José Miguel Garrido.)
+
+    Paraguay's 2014 DST will be as predicted.  (Thanks to Carlos Raúl Perasso.)
+
+    Better descriptions of countries with same time zone history as
+    Trinidad and Tobago since 1970.  (Thanks to Alan Barrett for suggestion.)
+
+    Several changes affect tz-link.htm, the main web page.
+
+      Mention Time.is (thanks to Even Scharning) and WX-now (thanks to
+      David Braverman).
+
+      Mention xCal (Internet RFC 6321) and jCal.
+
+      Microsoft has some support for tz database names.
+
+      CLDR data formats include both XML and JSON.
+
+      Mention Maggiolo's map of solar vs standard time.
+      (Thanks to Arthur David Olson.)
+
+      Mention TZ4Net.  (Thanks to Matt Johnson.)
+
+      Mention the timezone-olson Haskell package.
+
+      Mention zeitverschiebung.net.  (Thanks to Martin Jäger.)
+
+      Remove moribund links to daylight-savings-time.info and to
+      Simple Timer + Clocks.
+
+      Update two links.  (Thanks to Oscar van Vlijmen.)
+
+      Fix some formatting glitches, e.g., remove random newlines from
+      abbr elements' title attributes.
+
+
+Release 2013i - 2013-12-17 07:25:23 -0800
+
+  Changes affecting near-future timestamps:
+
+    Jordan switches back to standard time at 00:00 on December 20, 2013.
+    The 2006-2011 transition schedule is planned to resume in 2014.
+    (Thanks to Steffen Thorsen.)
+
+  Changes affecting past timestamps:
+
+    In 2004, Cuba began DST on March 28, not April 4.
+    (Thanks to Steffen Thorsen.)
+
+  Changes affecting code
+
+    The compile-time flag NOSOLAR has been removed, as nowadays the
+    benefit of slightly shrinking runtime table size is outweighed by the
+    cost of disallowing potential future updates that exceed old limits.
+
+  Changes affecting documentation and commentary
+
+    The files solar87, solar88, and solar89 are no longer distributed.
+    They were a negative experiment - that is, a demonstration that
+    tz data can represent solar time only with some difficulty and error.
+    Their presence in the distribution caused confusion, as Riyadh
+    civil time was generally not solar time in those years.
+
+    tz-link.htm now mentions Noda Time.  (Thanks to Matt Johnson.)
+
+
+Release 2013h - 2013-10-25 15:32:32 -0700
+
+  Changes affecting current and future timestamps:
+
+    Libya has switched its UT offset back to +02 without DST, instead
+    of +01 with DST.  (Thanks to Even Scharning.)
+
+    Western Sahara (Africa/El_Aaiun) uses Morocco's DST rules.
+    (Thanks to Gwillim Law.)
+
+  Changes affecting future timestamps:
+
+    Acre and (we guess) western Amazonas will switch from UT -04 to -05
+    on 2013-11-10.  This affects America/Rio_Branco and America/Eirunepe.
+    (Thanks to Steffen Thorsen.)
+
+    Add entries for DST transitions in Morocco in the year 2038.
+    This avoids some year-2038 glitches introduced in 2013g.
+    (Thanks to Yoshito Umaoka for reporting the problem.)
+
+  Changes affecting API
+
+    The 'tzselect' command no longer requires the 'select' command,
+    and should now work with /bin/sh on more platforms.  It also works
+    around a bug in BusyBox awk before version 1.21.0.  (Thanks to
+    Patrick 'P. J.' McDermott and Alan Barrett.)
+
+  Changes affecting code
+
+    Fix localtime overflow bugs with 32-bit unsigned time_t.
+
+    zdump no longer assumes sscanf returns maximal values on overflow.
+
+  Changes affecting the build procedure
+
+    The builder can specify which programs to use, if any, instead of
+    'ar' and 'ranlib', and libtz.a is now built locally before being
+    installed.  (Thanks to Michael Forney.)
+
+    A dependency typo in the 'zdump' rule has been fixed.
+    (Thanks to Andrew Paprocki.)
+
+    The Makefile has been simplified by assuming that 'mkdir -p' and 'cp -f'
+    work as specified by POSIX.2-1992 or later; this is portable nowadays.
+
+    'make clean' no longer removes 'leapseconds', since it's
+    host-independent and is part of the distribution.
+
+    The unused makefile macros TZCSRCS, TZDSRCS, DATESRCS have been removed.
+
+  Changes affecting documentation and commentary
+
+    tz-link.htm now mentions TC TIMEZONE's draft time zone service protocol
+    (thanks to Mike Douglass) and TimezoneJS.Date (thanks to Jim Fehrle).
+
+    Update URLs in tz-link page.  Add URLs for Microsoft Windows, since
+    8.1 introduces tz support.  Remove URLs for Tru64 and UnixWare (no
+    longer maintained) and for old advisories.  SOFA now does C.
+
+Release 2013g - 2013-09-30 21:08:26 -0700
+
+  Changes affecting current and near-future timestamps
+
+    Morocco now observes DST from the last Sunday in March to the last
+    Sunday in October, not April to September respectively.  (Thanks
+    to Steffen Thorsen.)
+
+  Changes affecting 'zic'
+
+    'zic' now runs on platforms that lack both hard links and symlinks.
+    (Thanks to Theo Veenker for reporting the problem, for MinGW.)
+    Also, fix some bugs on platforms that lack hard links but have symlinks.
+
+    'zic -v' again warns that Asia/Tehran has no POSIX environment variable
+    to predict the far future, fixing a bug introduced in 2013e.
+
+  Changes affecting the build procedure
+
+    The 'leapseconds' file is again put into the tzdata tarball.
+    Also, 'leapseconds.awk', so tzdata is self-contained.  (Thanks to
+    Matt Burgess and Ian Abbott.)  The timestamps of these and other
+    dependent files in tarballs are adjusted more consistently.
+
+  Changes affecting documentation and commentary
+
+    The README file is now part of the data tarball as well as the code.
+    It now states that files are public domain unless otherwise specified.
+    (Thanks to Andrew Main (Zefram) for asking for clarifications.)
+    Its details about the 1989 release moved to a place of honor near
+    the end of NEWS.
+
+
+Release 2013f - 2013-09-24 23:37:36 -0700
+
+  Changes affecting near-future timestamps
+
+    Tocantins will very likely not observe DST starting this spring.
+    (Thanks to Steffen Thorsen.)
+
+    Jordan will likely stay at UT +03 indefinitely, and will not fall
+    back this fall.
+
+    Palestine will fall back at 00:00, not 01:00.  (Thanks to Steffen Thorsen.)
+
+  Changes affecting API
+
+    The types of the global variables 'timezone' and 'altzone' (if present)
+    have been changed back to 'long'.  This is required for 'timezone'
+    by POSIX, and for 'altzone' by common practice, e.g., Solaris 11.
+    These variables were originally 'long' in the tz code, but were
+    mistakenly changed to 'time_t' in 1987; nobody reported the
+    incompatibility until now.  The difference matters on x32, where
+    'long' is 32 bits and 'time_t' is 64.  (Thanks to Elliott Hughes.)
+
+  Changes affecting the build procedure
+
+    Avoid long strings in leapseconds.awk to work around a mawk bug.
+    (Thanks to Cyril Baurand.)
+
+  Changes affecting documentation and commentary
+
+    New file 'NEWS' that contains release notes like this one.
+
+    Paraguay's law does not specify DST transition time; 00:00 is customary.
+    (Thanks to Waldemar Villamayor-Venialbo.)
+
+    Minor capitalization fixes.
+
+  Changes affecting version-control only
+
+    The experimental GitHub repository now contains annotated and
+    signed tags for recent releases, e.g., '2013e' for Release 2013e.
+    Releases are tagged starting with 2012e; earlier releases were
+    done differently, and tags would either not have a simple name or
+    not exactly match what was released.
+
+    'make set-timestamps' is now simpler and a bit more portable.
+
+
+Release 2013e - 2013-09-19 23:50:04 -0700
+
+  Changes affecting near-future timestamps
+
+    This year Fiji will start DST on October 27, not October 20.
+    (Thanks to David Wheeler for the heads-up.)  For now, guess that
+    Fiji will continue to spring forward the Sunday before the fourth
+    Monday in October.
+
+  Changes affecting current and future time zone abbreviations
+
+    Use WIB/WITA/WIT rather than WIT/CIT/EIT for alphabetic Indonesian
+    time zone abbreviations since 1932.  (Thanks to George Ziegler,
+    Priyadi Iman Nurcahyo, Zakaria, Jason Grimes, Martin Pitt, and
+    Benny Lin.)  This affects Asia/Dili, Asia/Jakarta, Asia/Jayapura,
+    Asia/Makassar, and Asia/Pontianak.
+
+    Use ART (UT -03, standard time), rather than WARST (also -03, but
+    daylight saving time) for San Luis, Argentina since 2009.
+
+  Changes affecting Godthåb timestamps after 2037 if version mismatch
+
+    Allow POSIX-like TZ strings where the transition time's hour can
+    range from -167 through 167, instead of the POSIX-required 0
+    through 24.  E.g., TZ='FJT-12FJST,M10.3.1/146,M1.3.4/75' for the
+    new Fiji rules.  This is a more-compact way to represent
+    far-future timestamps for America/Godthab, America/Santiago,
+    Antarctica/Palmer, Asia/Gaza, Asia/Hebron, Asia/Jerusalem,
+    Pacific/Easter, and Pacific/Fiji.  Other zones are unaffected by
+    this change.  (Derived from a suggestion by Arthur David Olson.)
+
+    Allow POSIX-like TZ strings where daylight saving time is in
+    effect all year.  E.g., TZ='WART4WARST,J1/0,J365/25' for Western
+    Argentina Summer Time all year.  This supports a more-compact way
+    to represent the 2013d data for America/Argentina/San_Luis.
+    Because of the change for San Luis noted above this change does not
+    affect the current data.  (Thanks to Andrew Main (Zefram) for
+    suggestions that improved this change.)
+
+    Where these two TZ changes take effect, there is a minor extension
+    to the tz file format in that it allows new values for the
+    embedded TZ-format string, and the tz file format version number
+    has therefore been increased from 2 to 3 as a precaution.
+    Version-2-based client code should continue to work as before for
+    all timestamps before 2038.  Existing version-2-based client code
+    (tzcode, GNU/Linux, Solaris) has been tested on version-3-format
+    files, and typically works in practice even for timestamps after
+    2037; the only known exception is America/Godthab.
+
+  Changes affecting timestamps before 1970
+
+    Pacific/Johnston is now a link to Pacific/Honolulu.  This corrects
+    some errors before 1947.
+
+    Some zones have been turned into links, when they differ from existing
+    zones only in older data entries that were likely invented or that
+    differ only in LMT or transitions from LMT.  These changes affect
+    only timestamps before 1943.  The affected zones are:
+    Africa/Juba, America/Anguilla, America/Aruba, America/Dominica,
+    America/Grenada, America/Guadeloupe, America/Marigot,
+    America/Montserrat, America/St_Barthelemy, America/St_Kitts,
+    America/St_Lucia, America/St_Thomas, America/St_Vincent,
+    America/Tortola, and Europe/Vaduz.  (Thanks to Alois Treindl for
+    confirming that the old Europe/Vaduz zone was wrong and the new
+    link is better for WWII-era times.)
+
+    Change Kingston Mean Time from -5:07:12 to -5:07:11.  This affects
+    America/Cayman, America/Jamaica and America/Grand_Turk timestamps
+    from 1890 to 1912.
+
+    Change the UT offset of Bern Mean Time from 0:29:44 to 0:29:46.
+    This affects Europe/Zurich timestamps from 1853 to 1894.  (Thanks
+    to Alois Treindl).
+
+    Change the date of the circa-1850 Zurich transition from 1849-09-12
+    to 1853-07-16, overriding Shanks with data from Messerli about
+    postal and telegraph time in Switzerland.
+
+  Changes affecting time zone abbreviations before 1970
+
+    For Asia/Jakarta, use BMT (not JMT) for mean time from 1923 to 1932,
+    as Jakarta was called Batavia back then.
+
+  Changes affecting API
+
+    The 'zic' command now outputs a dummy transition when far-future
+    data can't be summarized using a TZ string, and uses a 402-year
+    window rather than a 400-year window.  For the current data, this
+    affects only the Asia/Tehran file.  It does not affect any of the
+    timestamps that this file represents, so zdump outputs the same
+    information as before.  (Thanks to Andrew Main (Zefram).)
+
+    The 'date' command has a new '-r' option, which lets you specify
+    the integer time to display, a la FreeBSD.
+
+    The 'tzselect' command has two new options '-c' and '-n', which lets you
+    select a zone based on latitude and longitude.
+
+    The 'zic' command's '-v' option now warns about constructs that
+    require the new version-3 binary file format.  (Thanks to Arthur
+    David Olson for the suggestion.)
+
+    Support for floating-point time_t has been removed.
+    It was always dicey, and POSIX no longer requires it.
+    (Thanks to Eric Blake for suggesting to the POSIX committee to
+    remove it, and thanks to Alan Barrett, Clive D.W. Feather, Andy
+    Heninger, Arthur David Olson, and Alois Treindl, for reporting
+    bugs and elucidating some of the corners of the old floating-point
+    implementation.)
+
+    The signatures of 'offtime', 'timeoff', and 'gtime' have been
+    changed back to the old practice of using 'long' to represent UT
+    offsets.  This had been inadvertently and mistakenly changed to
+    'int_fast32_t'.  (Thanks to Christos Zoulas.)
+
+    The code avoids undefined behavior on integer overflow in some
+    more places, including gmtime, localtime, mktime and zdump.
+
+  Changes affecting the zdump utility
+
+    zdump now outputs "UT" when referring to Universal Time, not "UTC".
+    "UTC" does not make sense for timestamps that predate the introduction
+    of UTC, whereas "UT", a more-generic term, does.  (Thanks to Steve Allen
+    for clarifying UT vs UTC.)
+
+  Data changes affecting behavior of tzselect and similar programs
+
+    Country code BQ is now called the more-common name "Caribbean Netherlands"
+    rather than the more-official "Bonaire, St Eustatius & Saba".
+
+    Remove from zone.tab the names America/Montreal, America/Shiprock,
+    and Antarctica/South_Pole, as they are equivalent to existing
+    same-country-code zones for post-1970 timestamps.  The data entries for
+    these names are unchanged, so the names continue to work as before.
+
+  Changes affecting code internals
+
+    zic -c now runs way faster on 64-bit hosts when given large numbers.
+
+    zic now uses vfprintf to avoid allocating and freeing some memory.
+
+    tzselect now computes the list of continents from the data,
+    rather than have it hard-coded.
+
+    Minor changes pacify GCC 4.7.3 and GCC 4.8.1.
+
+  Changes affecting the build procedure
+
+    The 'leapseconds' file is now generated automatically from a
+    new file 'leap-seconds.list', which is a copy of
+    <ftp://ftp.nist.gov/pub/time/leap-seconds.list>
+    A new source file 'leapseconds.awk' implements this.
+    The goal is simplification of the future maintenance of 'leapseconds'.
+
+    When building the 'posix' or 'right' subdirectories, if the
+    subdirectory would be a copy of the default subdirectory, it is
+    now made a symbolic link if that is supported.  This saves about
+    2 MB of file system space.
+
+    The links America/Shiprock and Antarctica/South_Pole have been
+    moved to the 'backward' file.  This affects only nondefault builds
+    that omit 'backward'.
+
+  Changes affecting version-control only
+
+    .gitignore now ignores 'date'.
+
+  Changes affecting documentation and commentary
+
+    Changes to the 'tzfile' man page
+
+      It now mentions that the binary file format may be extended in
+      future versions by appending data.
+
+      It now refers to the 'zdump' and 'zic' man pages.
+
+    Changes to the 'zic' man page
+
+      It lists conditions that elicit a warning with '-v'.
+
+      It says that the behavior is unspecified when duplicate names
+      are given, or if the source of one link is the target of another.
+
+      Its examples are updated to match the latest data.
+
+      The definition of white space has been clarified slightly.
+      (Thanks to Michael Deckers.)
+
+    Changes to the 'Theory' file
+
+      There is a new section about the accuracy of the tz database,
+      describing the many ways that errors can creep in, and
+      explaining why so many of the pre-1970 timestamps are wrong or
+      misleading (thanks to Steve Allen, Lester Caine, and Garrett
+      Wollman for discussions that contributed to this).
+
+      The 'Theory' file describes LMT better (this follows a
+      suggestion by Guy Harris).
+
+      It refers to the 2013 edition of POSIX rather than the 2004 edition.
+
+      It's mentioned that excluding 'backward' should not affect the
+      other data, and it suggests at least one zone.tab name per
+      inhabited country (thanks to Stephen Colebourne).
+
+      Some longstanding restrictions on names are documented, e.g.,
+      'America/New_York' precludes 'America/New_York/Bronx'.
+
+      It gives more reasons for the 1970 cutoff.
+
+      It now mentions which time_t variants are supported, such as
+      signed integer time_t.  (Thanks to Paul Goyette for reporting
+      typos in an experimental version of this change.)
+
+      (Thanks to Philip Newton for correcting typos in these changes.)
+
+    Documentation and commentary is more careful to distinguish UT in
+    general from UTC in particular.  (Thanks to Steve Allen.)
+
+    Add a better source for the Zurich 1894 transition.
+    (Thanks to Pierre-Yves Berger.)
+
+    Update shapefile citations in tz-link.htm.  (Thanks to Guy Harris.)
+
+
+Release 2013d - 2013-07-05 07:38:01 -0700
+
+  Changes affecting future timestamps:
+
+    Morocco's midsummer transitions this year are July 7 and August 10,
+    not July 9 and August 8.  (Thanks to Andrew Paprocki.)
+
+    Israel now falls back on the last Sunday of October.
+    (Thanks to Ephraim Silverberg.)
+
+  Changes affecting past timestamps:
+
+    Specify Jerusalem's location more precisely; this changes the pre-1880
+    times by 2 s.
+
+  Changing affecting metadata only:
+
+    Fix typos in the entries for country codes BQ and SX.
+
+  Changes affecting code:
+
+    Rework the code to fix a bug with handling Australia/Macquarie on
+    32-bit hosts (thanks to Arthur David Olson).
+
+    Port to platforms like NetBSD, where time_t can be wider than long.
+
+    Add support for testing time_t types other than the system's.
+    Run 'make check_time_t_alternatives' to try this out.
+    Currently, the tests fail for unsigned time_t;
+    this should get fixed at some point.
+
+  Changes affecting documentation and commentary:
+
+    Deemphasize the significance of national borders.
+
+    Update the zdump man page.
+
+    Remove obsolete NOID comment (thanks to Denis Excoffier).
+
+    Update several URLs and comments in the web pages.
+
+    Spelling fixes (thanks to Kevin Lyda and Jonathan Leffler).
+
+    Update URL for CLDR Zone->Tzid table (thanks to Yoshito Umaoka).
+
+
+Release 2013c - 2013-04-19 16:17:40 -0700
+
+  Changes affecting current and future timestamps:
+
+    Palestine observed DST starting March 29, 2013.  (Thanks to
+    Steffen Thorsen.)  From 2013 on, Gaza and Hebron both observe DST,
+    with the predicted rules being the last Thursday in March at 24:00
+    to the first Friday on or after September 21 at 01:00.
+
+    Assume that the recent change to Paraguay's DST rules is permanent,
+    by moving the end of DST to the 4th Sunday in March every year.
+    (Thanks to Carlos Raúl Perasso.)
+
+  Changes affecting past timestamps:
+
+    Fix some historical data for Palestine to agree with that of
+    timeanddate.com, as follows:
+
+	  The spring 2008 change in Gaza and Hebron was on 00:00 Mar 28, not
+	  00:00 Apr 1.
+
+	  The fall 2009 change in Gaza and Hebron on Sep 4 was at 01:00, not
+	  02:00.
+
+	  The spring 2010 change in Hebron was 00:00 Mar 26, not 00:01 Mar 27.
+
+	  The spring 2011 change in Gaza was 00:01 Apr 1, not 12:01 Apr 2.
+
+	  The spring 2011 change in Hebron on Apr 1 was at 00:01, not 12:01.
+
+	  The fall 2011 change in Hebron on Sep 30 was at 00:00, not 03:00.
+
+    Fix times of habitation for Macquarie to agree with the Tasmania
+    Parks & Wildlife Service history, which indicates that permanent
+    habitation was 1899-1919 and 1948 on.
+
+  Changing affecting metadata only:
+
+    Macquarie Island is politically part of Australia, not Antarctica.
+    (Thanks to Tobias Conradi.)
+
+    Sort Macquarie more-consistently with other parts of Australia.
+    (Thanks to Tim Parenti.)
+
+
+Release 2013b - 2013-03-10 22:33:40 -0700
+
+  Changes affecting current and future timestamps:
+
+    Haiti uses US daylight-saving rules this year, and presumably future years.
+    This changes timestamps starting today.  (Thanks to Steffen Thorsen.)
+
+    Paraguay will end DST on March 24 this year.
+    (Thanks to Steffen Thorsen.)  For now, assume it's just this year.
+
+    Morocco does not observe DST during Ramadan;
+    try to predict Ramadan in Morocco as best we can.
+    (Thanks to Erik Homoet for the heads-up.)
+
+  Changes affecting commentary:
+
+    Update URLs in tz-link page.  Add URLs for webOS, BB10, iOS.
+    Update URL for Solaris.  Mention Internet RFC 6557.
+    Update Internet RFCs 2445->5545, 2822->5322.
+    Switch from FTP to HTTP for Internet RFCs.
+
+
+Release 2013a - 2013-02-27 09:20:35 -0800
+
+  Change affecting binary data format:
+
+    The zone offset at the end of version-2-format zone files is now
+    allowed to be 24:00, as per POSIX.1-2008.  (Thanks to Arthur David Olson.)
+
+  Changes affecting current and future timestamps:
+
+    Chile's 2013 rules, and we guess rules for 2014 and later, will be
+    the same as 2012, namely Apr Sun>=23 03:00 UTC to Sep Sun>=2 04:00 UTC.
+    (Thanks to Steffen Thorsen and Robert Elz.)
+
+    New Zones Asia/Khandyga, Asia/Ust-Nera, Europe/Busingen.
+    (Thanks to Tobias Conradi and Arthur David Olson.)
+
+  Many changes affect historical timestamps before 1940.
+  These were deduced from: Milne J. Civil time. Geogr J. 1899
+  Feb;13(2):173-94 <https://www.jstor.org/stable/1774359>.
+
+  Changes affecting the code:
+
+    Fix zic bug that mishandled Egypt's 2010 changes (this also affected
+    the data).  (Thanks to Arthur David Olson.)
+
+    Fix localtime bug when time_t is unsigned and data files were generated
+    by a signed time_t system.  (Thanks to Doug Bailey for reporting and
+    to Arthur David Olson for fixing.)
+
+    Allow the email address for bug reports to be set by the packager.
+    The default is tz@iana.org, as before.  (Thanks to Joseph S. Myers.)
+
+    Update HTML checking to be compatible with Ubuntu 12.10.
+
+    Check that files are a safe subset of ASCII.  At some point we may
+    relax this requirement to a safe subset of UTF-8.  Without the
+    check, some non-UTF-8 encodings were leaking into the distribution.
+
+  Commentary changes:
+
+    Restore a comment about copyright notices that was inadvertently deleted.
+    (Thanks to Arthur David Olson.)
+
+    Improve the commentary about which districts observe what times
+    in Russia.  (Thanks to Oscar van Vlijmen and Arthur David Olson).
+
+    Add web page links to tz.js.
+
+    Add "Run by the Monkeys" to tz-art.  (Thanks to Arthur David Olson.)
+
+
+Release 2012j - 2012-11-12 18:34:49 -0800
+
+  Libya moved to CET this weekend, but with DST planned next year.
+  (Thanks to Even Scharning, Steffen Thorsen, and Tim Parenti.)
+
+  Signatures now have the extension .asc, not .sign, as that's more
+  standard.  (Thanks to Phil Pennock.)
+
+  The output of 'zdump --version', and of 'zic --version', now
+  uses a format that is more typical for --version.
+  (Thanks to Joseph S. Myers.)
+
+  The output of 'tzselect --help', 'zdump --help', and 'zic --help'
+  now uses tz@iana.org rather than the old elsie address.
+
+  zic -v now complains about abbreviations that are less than 3
+  or more than 6 characters, as per Posix.  Formerly, it checked
+  for abbreviations that were more than 3.
+
+  'make public' no longer puts its temporary directory under /tmp,
+  and uses the just-built zic rather than the system zic.
+
+  Various fixes to documentation and commentary.
+
+
+Release 2012i - 2012-11-03 12:57:09 -0700
+
+  Cuba switches from DST tomorrow at 01:00.  (Thanks to Steffen Thorsen.)
+
+  Linker flags can now be specified via LDFLAGS.
+  AWK now defaults to 'awk', not 'nawk'.
+  The shell in tzselect now defaults to /bin/bash, but this can
+  be overridden by specifying KSHELL.
+  The main web page now mentions the unofficial GitHub repository.
+  (Thanks to Mike Frysinger.)
+
+  Tarball signatures can now be built by running 'make signatures'.
+  There are also new makefile rules 'tarballs', 'check_public', and
+  separate makefile rules for each tarball and signature file.
+  A few makefile rules are now more portable to strict POSIX.
+
+  The main web page now lists the canonical IANA URL.
+
+
+Release 2012h - 2012-10-26 22:49:10 -0700
+
+  Bahia no longer has DST.  (Thanks to Kelley Cook.)
+
+  Tocantins has DST.  (Thanks to Rodrigo Severo.)
+
+  Israel has new DST rules next year.  (Thanks to Ephraim Silverberg.)
+
+  Jordan stays on DST this winter.  (Thanks to Steffen Thorsen.)
+
+  Web page updates.
+
+  More C modernization, except that at Arthur David Olson's suggestion
+  the instances of 'register' were kept.
+
+
+Release 2012g - 2012-10-17 20:59:45 -0700
+
+  Samoa fall 2012 and later.  (Thanks to Nicholas Pereira and Robert Elz.)
+
+  Palestine fall 2012.  (Thanks to Steffen Thorsen.)
+
+  Assume C89.
+
+  To attack the version-number problem, this release ships the file
+  'Makefile' (which contains the release number) in both the tzcode and
+  the tzdata tarballs.  The two Makefiles are identical, and should be
+  identical in any matching pair of tarballs, so it shouldn't matter
+  which order you extract the tarballs.  Perhaps we can come up with a
+  better version-number scheme at some point; this scheme does have the
+  virtue of not adding more files.
+
+
+Release 2012f - 2012-09-12 23:17:03 -0700
+
+  * australasia (Pacific/Fiji): Fiji DST is October 21 through January
+    20 this year.  (Thanks to Steffen Thorsen.)
+
+
+Release 2012e - 2012-08-02 20:44:55 -0700
+
+  * australasia (Pacific/Fakaofo): Tokelau is UT +13, not +14.
+    (Thanks to Steffen Thorsen.)
+
+  * Use a single version number for both code and data.
+
+  * .gitignore: New file.
+
+  * Remove trailing white space.
+
+
+Release code2012c-data2012d - 2012-07-19 16:35:33 -0700
+
+  Changes for Morocco's timestamps, which take effect in a couple of
+  hours, along with infrastructure changes to accommodate how the tz
+  code and data are released on IANA.
+
+
+Release data2012c - 2012-03-27 12:17:25 -0400
+
+  africa
+	Summer time changes for Morocco (to start late April 2012)
+
+  asia
+	Changes for 2012 for Gaza & the West Bank (Hebron) and Syria
+
+  northamerica
+	Haiti following US/Canada rules for 2012 (and we're assuming,
+	for now anyway, for the future).
+
+
+Release 2012b - 2012-03-02 12:29:15 +0700
+
+  There is just one change to tzcode2012b (compared with 2012a):
+  the Makefile that was accidentally included with 2012a has been
+  replaced with the version that should have been there, which is
+  identical with the previous version (from tzcode2011i).
+
+  There are just two changes in tzdata2012b compared with 2012a.
+
+  Most significantly, summer time in Cuba has been delayed 3 weeks
+  (now starts April 1 rather than March 11).   Since Mar 11 (the old start
+  date, as listed in 2012a) is just a little over a week away, this
+  change is urgent.
+
+  Less importantly, an excess tab in one of the changes in zone.tab
+  in 2012a has been removed.
+
+
+Release 2012a - 2012-03-01 18:28:10 +0700
+
+  The changes in tzcode2012a (compared to the previous version, 2011i)
+  are entirely to the README and tz-art.htm and tz-link.htm files, if
+  none of those concern you, you can ignore the code update.  The changes
+  reflect the changed addresses for the mailing list and the code and
+  data distribution points & methods (and a link to DateTime::TimeZone::Tzfile
+  has been added to tz-link.htm).
+
+  In tzdata2012a (compared to the previous release, which was 2011n)
+  the major changes are:
+	Chile 2011/2012 and 2012/2013 summer time date adjustments.
+	Falkland Islands onto permanent summer time (we're assuming for the
+		foreseeable future, though 2012 is all we're fairly certain of.)
+	Armenia has abolished Summer Time.
+	Tokelau jumped the International Date Line back last December
+		(just the same as their near neighbour, Samoa).
+	America/Creston is a new zone for a small area of British Columbia
+	There will be a leapsecond 2012-06-30 23:59:60 UTC.
+
+  Other minor changes are:
+	Corrections to 1918 Canadian summer time end dates.
+	Updated URL for UK time zone history (in comments)
+	A few typos in Le Corre's list of free French place names (comments)
+
+
+Release data2011n - 2011-10-30 14:57:54 +0700
+
+  There are three changes of note - most urgently, Cuba (America/Havana)
+  has extended summer time by two weeks, now to end on Nov 13, rather than
+  the (already past) Oct 30.   Second, the Pridnestrovian Moldavian Republic
+  (Europe/Tiraspol) decided not to split from the rest of Moldova after
+  all, and consequently that zone has been removed (again) and reinstated
+  in the "backward" file as a link to Europe/Chisinau.   And third, the
+  end date for Fiji's summer time this summer was moved forward from the
+  earlier planned Feb 26, to Jan 22.
+
+  Apart from that, Moldova (MD) returns to a single entry in zone.tab
+  (and the incorrect syntax that was in the 2011m version of that file
+  is so fixed - it would have been fixed in a different way had this
+  change not happened - that's the "missing" sccs version id).
+
+
+Release data2011m - 2011-10-24 21:42:16 +0700
+
+  In particular, the typos in comments in the data (2011-11-17 should have
+  been 2011-10-17 as Alan Barrett noted, and spelling of Tiraspol that
+  Tim Parenti noted) have been fixed, and the change for Ukraine has been
+  made in all 4 Ukrainian zones, rather than just Kiev (again, thanks to
+  Tim Parenti, and also Denys Gavrysh)
+
+  In addition, I added Europe/Tiraspol to zone.tab.
+
+  This time, all the files have new version numbers...  (including the files
+  otherwise unchanged in 2011m that were changed in 2011l but didn't get new
+  version numbers there...)
+
+
+Release data2011l - 2011-10-10 11:15:43 +0700
+
+  There are just 2 changes that cause different generated tzdata files from
+  zic, to Asia/Hebron and Pacific/Fiji - the possible change for Bahia, Brazil
+  is included, but commented out.  Compared with the diff I sent out last week,
+  this version also includes attributions for the sources for the changes
+  (in much the same format as ado used, but the html tags have not been
+  checked, verified, or used in any way at all, so if there are errors there,
+  please let me know.)
+
+
+Release data2011k - 2011-09-20 17:54:03 -0400
+
+  [not summarized]
+
+
+Release data2011j - 2011-09-12 09:22:49 -0400
+
+  (contemporary changes for Samoa; past changes for Kenya, Uganda, and
+  Tanzania); there are also two spelling corrections to comments in
+  the australasia file (with thanks to Christos Zoulas).
+
+
+Release 2011i - 2011-08-29 05:56:32 -0400
+
+  [not summarized]
+
+
+Release data2011h - 2011-06-15 18:41:48 -0400
+
+  Russia and Curaçao changes
+
+
+Release 2011g - 2011-04-25 09:07:22 -0400
+
+  update the rules for Egypt to reflect its abandonment of DST this year
+
+
+Release 2011f - 2011-04-06 17:14:53 -0400
+
+  [not summarized]
+
+
+Release 2011e - 2011-03-31 16:04:38 -0400
+
+  Morocco, Chile, and tz-link changes
+
+
+Release 2011d - 2011-03-14 09:18:01 -0400
+
+  changes that impact present-day timestamps in Cuba, Samoa, and Turkey
+
+
+Release 2011c - 2011-03-07 09:30:09 -0500
+
+  These do affect current timestamps in Chile and Annette Island, Canada.
+
+
+Release 2011b - 2011-02-07 08:44:50 -0500
+
+  [not summarized]
+
+
+Release 2011a - 2011-01-24 10:30:16 -0500
+
+  [not summarized]
+
+
+Release data2010o - 2010-11-01 09:18:23 -0400
+
+  change to the end of DST in Fiji in 2011
+
+
+Release 2010n - 2010-10-25 08:19:17 -0400
+
+  [not summarized]
+
+
+Release 2010m - 2010-09-27 09:24:48 -0400
+
+  Hong Kong, Vostok, and zic.c changes
+
+
+Release 2010l - 2010-08-16 06:57:25 -0400
+
+  [not summarized]
+
+
+Release 2010k - 2010-07-26 10:42:27 -0400
+
+  [not summarized]
+
+
+Release 2010j - 2010-05-10 09:07:48 -0400
+
+  changes for Bahía de Banderas and for version naming
+
+
+Release data2010i - 2010-04-16 18:50:45 -0400
+
+  the end of DST in Morocco on 2010-08-08
+
+
+Release data2010h - 2010-04-05 09:58:56 -0400
+
+  [not summarized]
+
+
+Release data2010g - 2010-03-24 11:14:53 -0400
+
+  [not summarized]
+
+
+Release 2010f - 2010-03-22 09:45:46 -0400
+
+  [not summarized]
+
+
+Release data2010e - 2010-03-08 14:24:27 -0500
+
+  corrects the Dhaka bug found by Danvin Ruangchan
+
+
+Release data2010d - 2010-03-06 07:26:01 -0500
+
+  [not summarized]
+
+
+Release 2010c - 2010-03-01 09:20:58 -0500
+
+  changes including KRE's suggestion for earlier initialization of
+  "goahead" and "goback" structure elements
+
+
+Release code2010a - 2010-02-16 10:40:04 -0500
+
+  [not summarized]
+
+
+Release data2010b - 2010-01-20 12:37:01 -0500
+
+  Mexico changes
+
+
+Release data2010a - 2010-01-18 08:30:04 -0500
+
+  changes to Dhaka
+
+
+Release data2009u - 2009-12-26 08:32:28 -0500
+
+  changes to DST in Bangladesh
+
+
+Release 2009t - 2009-12-21 13:24:27 -0500
+
+  [not summarized]
+
+
+Release data2009s - 2009-11-14 10:26:32 -0500
+
+  (cosmetic) Antarctica change and the DST-in-Fiji-in-2009-and-2010 change
+
+
+Release 2009r - 2009-11-09 10:10:31 -0500
+
+  "antarctica" and "tz-link.htm" changes
+
+
+Release 2009q - 2009-11-02 09:12:40 -0500
+
+  with two corrections as reported by Eric Muller and Philip Newton
+
+
+Release data2009p - 2009-10-23 15:05:27 -0400
+
+  Argentina (including San Luis) changes (with the correction from
+  Mariano Absatz)
+
+
+Release data2009o - 2009-10-14 16:49:38 -0400
+
+  Samoa (commentary only), Pakistan, and Bangladesh changes
+
+
+Release data2009n - 2009-09-22 15:13:38 -0400
+
+  added commentary for Argentina and a change to the end of DST in
+  2009 in Pakistan
+
+
+Release data2009m - 2009-09-03 10:23:43 -0400
+
+  Samoa and Palestine changes
+
+
+Release data2009l - 2009-08-14 09:13:07 -0400
+
+  Samoa (comments only) and Egypt
+
+
+Release 2009k - 2009-07-20 09:46:08 -0400
+
+  [not summarized]
+
+
+Release data2009j - 2009-06-15 06:43:59 -0400
+
+  Bangladesh change (with a short turnaround since the DST change is
+  impending)
+
+
+Release 2009i - 2009-06-08 09:21:22 -0400
+
+  updating for DST in Bangladesh this year
+
+
+Release 2009h - 2009-05-26 09:19:14 -0400
+
+  [not summarized]
+
+
+Release data2009g - 2009-04-20 16:34:07 -0400
+
+  Cairo
+
+
+Release data2009f - 2009-04-10 11:00:52 -0400
+
+  correct DST in Pakistan
+
+
+Release 2009e - 2009-04-06 09:08:11 -0400
+
+  [not summarized]
+
+
+Release 2009d - 2009-03-23 09:38:12 -0400
+
+  Morocco, Tunisia, Argentina, and American Astronomical Society changes
+
+
+Release data2009c - 2009-03-16 09:47:51 -0400
+
+  change to the start of Cuban DST
+
+
+Release 2009b - 2009-02-09 11:15:22 -0500
+
+  [not summarized]
+
+
+Release 2009a - 2009-01-21 10:09:39 -0500
+
+  [not summarized]
+
+
+Release data2008i - 2008-10-21 12:10:25 -0400
+
+  southamerica and zone.tab files, with Argentina DST rule changes and
+  United States zone reordering and recommenting
+
+
+Release 2008h - 2008-10-13 07:33:56 -0400
+
+  [not summarized]
+
+
+Release 2008g - 2008-10-06 09:03:18 -0400
+
+  Fix a broken HTML anchor and update Brazil's DST transitions;
+  there's also a slight reordering of information in tz-art.htm.
+
+
+Release data2008f - 2008-09-09 22:33:26 -0400
+
+  [not summarized]
+
+
+Release 2008e - 2008-07-28 14:11:17 -0400
+
+  changes by Arthur David Olson and Jesper Nørgaard Welen
+
+
+Release data2008d - 2008-07-07 09:51:38 -0400
+
+  changes by Arthur David Olson, Paul Eggert, and Rodrigo Severo
+
+
+Release data2008c - 2008-05-19 17:48:03 -0400
+
+  Pakistan, Morocco, and Mongolia
+
+
+Release data2008b - 2008-03-24 08:30:59 -0400
+
+  including renaming Asia/Calcutta to Asia/Kolkata, with a backward
+  link provided
+
+
+Release 2008a - 2008-03-08 05:42:16 -0500
+
+  [not summarized]
+
+
+Release 2007k - 2007-12-31 10:25:22 -0500
+
+  most importantly, changes to the "southamerica" file based on
+  Argentina's readoption of daylight saving time
+
+
+Release 2007j - 2007-12-03 09:51:01 -0500
+
+  1. eliminate the "P" (parameter) macro;
+
+  2. the "noncontroversial" changes circulated on the time zone
+  mailing list (less the changes to "logwtmp.c");
+
+  3. eliminate "too many transition" errors when "min" is used in time
+  zone rules;
+
+  4. changes by Paul Eggert (including updated information for Venezuela).
+
+
+Release data2007i - 2007-10-30 10:28:11 -0400
+
+  changes for Cuba and Syria
+
+
+Release 2007h - 2007-10-01 10:05:51 -0400
+
+  changes by Paul Eggert, as well as an updated link to the ICU
+  project in tz-link.htm
+
+
+Release 2007g - 2007-08-20 10:47:59 -0400
+
+  changes by Paul Eggert
+
+  The "leapseconds" file has been updated to incorporate the most
+  recent International Earth Rotation and Reference Systems Service
+  (IERS) bulletin.
+
+  There's an addition to tz-art.htm regarding the television show "Medium".
+
+
+Release 2007f - 2007-05-07 10:46:46 -0400
+
+  changes by Paul Eggert (including Haiti, Turks and Caicos, and New
+  Zealand)
+
+  changes to zic.c to allow hour values greater than 24 (along with
+  Paul's improved time value overflow checking)
+
+
+Release 2007e - 2007-04-02 10:11:52 -0400
+
+  Syria and Honduras changes by Paul Eggert
+
+  zic.c variable renaming changes by Arthur David Olson
+
+
+Release 2007d - 2007-03-20 08:48:30 -0400
+
+  changes by Paul Eggert
+
+  the elimination of white space at the ends of lines
+
+
+Release 2007c - 2007-02-26 09:09:37 -0500
+
+  changes by Paul Eggert
+
+
+Release 2007b - 2007-02-12 09:34:20 -0500
+
+  Paul Eggert's proposed change to the quotation handling logic in zic.c.
+
+  changes to the commentary in "leapseconds" reflecting the IERS
+  announcement that there is to be no positive leap second at the end
+  of June 2007.
+
+
+Release 2007a - 2007-01-08 12:28:29 -0500
+
+  changes by Paul Eggert
+
+  Derick Rethan's Asmara change
+
+  Oscar van Vlijmen's Easter Island local mean time change
+
+  symbolic link changes
+
+
+Release 2006p - 2006-11-27 08:54:27 -0500
+
+  changes by Paul Eggert
+
+
+Release 2006o - 2006-11-06 09:18:07 -0500
+
+  changes by Paul Eggert
+
+
+Release 2006n - 2006-10-10 11:32:06 -0400
+
+  changes by Paul Eggert
+
+
+Release 2006m - 2006-10-02 15:32:35 -0400
+
+  changes for Uruguay, Palestine, and Egypt by Paul Eggert
+
+  (minimalist) changes to zic.8 to clarify "until" information
+
+
+Release data2006l - 2006-09-18 12:58:11 -0400
+
+  Paul's best-effort work on this coming weekend's Egypt time change
+
+
+Release 2006k - 2006-08-28 12:19:09 -0400
+
+  changes by Paul Eggert
+
+
+Release 2006j - 2006-08-21 09:56:32 -0400
+
+  changes by Paul Eggert
+
+
+Release code2006i - 2006-08-07 12:30:55 -0400
+
+  localtime.c fixes
+
+  Ken Pizzini's conversion script
+
+
+Release code2006h - 2006-07-24 09:19:37 -0400
+
+  adds public domain notices to four files
+
+  includes a fix for transition times being off by a second
+
+  adds a new recording to the "arts" file (information courtesy Colin Bowern)
+
+
+Release 2006g - 2006-05-08 17:18:09 -0400
+
+  northamerica changes by Paul Eggert
+
+
+Release 2006f - 2006-05-01 11:46:00 -0400
+
+  a missing version number problem is fixed (with thanks to Bradley
+  White for catching the problem)
+
+
+Release 2006d - 2006-04-17 14:33:43 -0400
+
+  changes by Paul Eggert
+
+  added new items to tz-arts.htm that were found by Paul
+
+
+Release 2006c - 2006-04-03 10:09:32 -0400
+
+  two sets of data changes by Paul Eggert
+
+  a fencepost error fix in zic.c
+
+  changes to zic.c and the "europe" file to minimize differences
+  between output produced by the old 32-bit zic and the new 64-bit
+  version
+
+
+Release 2006b - 2006-02-20 10:08:18 -0500
+  [tz32code2006b + tz64code2006b + tzdata2006b]
+
+  64-bit code
+
+  All SCCS IDs were bumped to "8.1" for this release.
+
+
+Release 2006a - 2006-01-30 08:59:31 -0500
+
+  changes by Paul Eggert (in particular, Indiana time zone moves)
+
+  an addition to the zic manual page to describe how special-case
+  transitions are handled
+
+
+Release 2005r - 2005-12-27 09:27:13 -0500
+
+  Canadian changes by Paul Eggert
+
+  They also add "<pre>" directives to time zone data files and reflect
+  changes to warning message logic in "zdump.c" (but with calls to
+  "gettext" kept unbundled at the suggestion of Ken Pizzini).
+
+
+Release 2005q - 2005-12-13 09:17:09 -0500
+
+  Nothing earth-shaking here:
+	1.  Electronic mail addresses have been removed.
+	2.  Casts of the return value of exit have been removed.
+	3.  Casts of the argument of is.* macros have been added.
+	4.  Indentation in one section of zic.c has been fixed.
+	5.  References to dead URLs in the data files have been dealt with.
+
+
+Release 2005p - 2005-12-05 10:30:53 -0500
+
+  "systemv", "tz-link.htm", and "zdump.c" changes
+  (less the casts of arguments to the is* macros)
+
+
+Release 2005o - 2005-11-28 10:55:26 -0500
+
+  Georgia, Cuba, Nicaragua, and Jordan changes by Paul Eggert
+
+  zdump.c lint fixes by Arthur David Olson
+
+
+Release 2005n - 2005-10-03 09:44:09 -0400
+
+  changes by Paul Eggert (both the Uruguay changes and the Kyrgyzstan
+  et al. changes)
+
+
+Release 2005m - 2005-08-29 12:15:40 -0400
+
+  changes by Paul Eggert (with a small tweak to the tz-art change)
+
+  a declaration of an unused variable has been removed from zdump.c
+
+
+Release 2005l - 2005-08-22 12:06:39 -0400
+
+  changes by Paul Eggert
+
+  overflow/underflow checks by Arthur David Olson, minus changes to
+  the "Theory" file about the pending addition of 64-bit data (I grow
+  less confident of the changes being accepted with each passing day,
+  and the changes no longer increase the data files nine-fold--there's
+  less than a doubling in size by my local Sun's reckoning)
+
+
+Release 2005k - 2005-07-14 14:14:24 -0400
+
+  The "leapseconds" file has been edited to reflect the recently
+  announced leap second at the end of 2005.
+
+  I've also deleted electronic mail addresses from the files as an
+  anti-spam measure.
+
+
+Release 2005j - 2005-06-13 14:34:13 -0400
+
+  These reflect changes to limit the length of time zone abbreviations
+  and the characters used in those abbreviations.
+
+  There are also changes to handle POSIX-style "quoted" time zone
+  environment variables.
+
+  The changes were circulated on the time zone mailing list; the only
+  change since then was the removal of a couple of minimum-length of
+  abbreviation checks.
+
+
+Release data2005i - 2005-04-21 15:04:16 -0400
+
+  changes (most importantly to Nicaragua and Haiti) by Paul Eggert
+
+
+Release 2005h - 2005-04-04 11:24:47 -0400
+
+  changes by Paul Eggert
+
+  minor changes to Makefile and zdump.c to produce more useful output
+  when doing a "make typecheck"
+
+
+Release 2005g - 2005-03-14 10:11:21 -0500
+
+  changes by Paul Eggert (a change to current DST rules in Uruguay and
+  an update to a link to time zone software)
+
+
+Release 2005f - 2005-03-01 08:45:32 -0500
+
+  data and documentation changes by Paul Eggert
+
+
+Release 2005e - 2005-02-10 15:59:44 -0500
+
+  [not summarized]
+
+
+Release code2005d - 2005-01-31 09:21:47 -0500
+
+  make zic complain about links to links if the -v flag is used
+
+  have "make public" do more code checking
+
+  add an include to "localtime.c" for the benefit of gcc systems
+
+
+Release 2005c - 2005-01-17 18:36:29 -0500
+
+  get better results when mktime runs on a system where time_t is double
+
+  changes to the data files (most importantly to Paraguay)
+
+
+Release 2005b - 2005-01-10 09:19:54 -0500
+
+  Get localtime and gmtime working on systems with exotic time_t types.
+
+  Update the leap second commentary in the "leapseconds" file.
+
+
+Release 2005a - 2005-01-01 13:13:44 -0500
+
+  [not summarized]
+
+
+Release code2004i - 2004-12-14 13:42:58 -0500
+
+  Deal with systems where time_t is unsigned.
+
+
+Release code2004h - 2004-12-07 11:40:18 -0500
+
+  64-bit-time_t changes
+
+
+Release 2004g - 2004-11-02 09:06:01 -0500
+
+  update to Cuba (taking effect this weekend)
+
+  other changes by Paul Eggert
+
+  correction of the spelling of Oslo
+
+  changed versions of difftime.c and private.h
+
+
+Release code2004f - 2004-10-21 10:25:22 -0400
+
+  Cope with wide-ranging tm_year values.
+
+
+Release 2004e - 2004-10-11 14:47:21 -0400
+
+  Brazil/Argentina/Israel changes by Paul Eggert
+
+  changes to tz-link.htm by Paul
+
+  one small fix to Makefile
+
+
+Release 2004d - 2004-09-22 08:27:29 -0400
+
+  Avoid overflow problems when TM_YEAR_BASE is added to an integer.
+
+
+Release 2004c - 2004-08-11 12:06:26 -0400
+
+  asctime-related changes
+
+  (variants of) some of the documentation changes suggested by Paul Eggert
+
+
+Release 2004b - 2004-07-19 14:33:35 -0400
+
+  data changes by Paul Eggert - most importantly, updates for Argentina
+
+
+Release 2004a - 2004-05-27 12:00:47 -0400
+
+  changes by Paul Eggert
+
+  Handle DST transitions that occur at the end of a month in some
+  years but at the start of the following month in other years.
+
+  Add a copy of the correspondence that's the basis for claims about
+  DST in the Navajo Nation.
+
+
+Release 2003e - 2003-12-15 09:36:47 -0500
+
+  changes by Arthur David Olson (primarily code changes)
+
+  changes by Paul Eggert (primarily data changes)
+
+  minor changes to "Makefile" and "northamerica" (in the latter case,
+  optimization of the "Toronto" rules)
+
+
+Release 2003d - 2003-10-06 09:34:44 -0400
+
+  changes by Paul Eggert
+
+
+Release 2003c - 2003-09-16 10:47:05 -0400
+
+  Fix bad returns in zic.c's inleap function.
+  Thanks to Bradley White for catching the problem!
+
+
+Release 2003b - 2003-09-16 07:13:44 -0400
+
+  Add a "--version" option (and documentation) to the zic and zdump commands.
+
+  changes to overflow/underflow checking in zic
+
+  a localtime typo fix.
+
+  Update the leapseconds and tz-art.htm files.
+
+
+Release 2003a - 2003-03-24 09:30:54 -0500
+
+  changes by Paul Eggert
+
+  a few additions and modifications to the tz-art.htm file
+
+
+Release 2002d - 2002-10-15 13:12:42 -0400
+
+  changes by Paul Eggert, less the "Britain (UK)" change in iso3166.tab
+
+  There's also a new time zone quote in "tz-art.htm".
+
+
+Release 2002c - 2002-04-04 11:55:20 -0500
+
+  changes by Paul Eggert
+
+  Change zic.c to avoid creating symlinks to files that don't exist.
+
+
+Release 2002b - 2002-01-28 12:56:03 -0500
+
+  [These change notes are for Release 2002a, which was corrupted.
+  2002b was a corrected version of 2002a.]
+
+  changes by Paul Eggert
+
+  Update the "leapseconds" file to note that there'll be no leap
+  second at the end of June, 2002.
+
+  Change "zic.c" to deal with a problem in handling the "Asia/Bishkek" zone.
+
+  Change to "difftime.c" to avoid sizeof problems.
+
+
+Release 2001d - 2001-10-09 13:31:32 -0400
+
+  changes by Paul Eggert
+
+
+Release 2001c - 2001-06-05 13:59:55 -0400
+
+  changes by Paul Eggert and Andrew Brown
+
+
+Release 2001b - 2001-04-05 16:44:38 -0400
+
+  changes by Paul Eggert (modulo jnorgard's typo fix)
+
+  tz-art.htm has been HTMLified.
+
+
+Release 2001a - 2001-03-13 12:57:44 -0500
+
+  changes by Paul Eggert
+
+  An addition to the "leapseconds" file: comments with the text of the
+  latest IERS leap second notice.
+
+  Trailing white space has been removed from data file lines, and
+  repeated spaces in "Rule Jordan" lines in the "asia" file have been
+  converted to tabs.
+
+
+Release 2000h - 2000-12-14 15:33:38 -0500
+
+  changes by Paul Eggert
+
+  one typo fix in the "art" file
+
+  With providence, this is the last update of the millennium.
+
+
+Release 2000g - 2000-10-10 11:35:22 -0400
+
+  changes by Paul Eggert
+
+  correction of John Mackin's name submitted by Robert Elz
+
+  Garry Shandling's Daylight Saving Time joke (!?!) from the recent
+  Emmy Awards broadcast.
+
+
+Release 2000f - 2000-08-10 09:31:58 -0400
+
+  changes by Paul Eggert
+
+  Added information in "tz-art.htm" on a Seinfeld reference to DST.
+
+  Error checking and messages in the "yearistype" script have been
+  improved.
+
+
+Release 2000e - 2000-07-31 09:27:54 -0400
+
+  data changes by Paul Eggert
+
+  a change to the default value of the defined constant HAVE_STRERROR
+
+  the addition of a Dave Barry quote on DST to the tz-arts file
+
+
+Release 2000d - 2000-04-20 15:43:04 -0400
+
+  changes to the documentation and code of strftime for C99 conformance
+
+  a bug fix for date.c
+
+  These are based on (though modified from) changes by Paul Eggert.
+
+
+Release 2000c - 2000-03-04 10:31:43 -0500
+
+  changes by Paul Eggert
+
+
+Release 2000b - 2000-02-21 12:16:29 -0500
+
+  changes by Paul Eggert and Joseph Myers
+
+  modest tweaks to the tz-art.htm and tz-link.htm files
+
+
+Release 2000a - 2000-01-18 09:21:26 -0500
+
+  changes by Paul Eggert
+
+  The two hypertext documents have also been renamed.
+
+
+Release code1999i-data1999j - 1999-11-15 18:43:22 -0500
+
+  Paul Eggert's changes
+
+  additions to the "zic" manual page and the "Arts.htm" file
+
+
+Release code1999h-data1999i - 1999-11-08 14:55:21 -0500
+
+  [not summarized]
+
+
+Release data1999h - 1999-10-07 03:50:29 -0400
+
+  changes by Paul Eggert to "europe" (most importantly, fixing
+  Lithuania and Estonia)
+
+
+Release 1999g - 1999-09-28 11:06:18 -0400
+
+  data changes by Paul Eggert (most importantly, the change for
+  Lebanon that buys correctness for this coming Sunday)
+
+  The "code" file contains changes to "Makefile" and "checktab.awk" to
+  allow better checking of time zone files before they are published.
+
+
+Release 1999f - 1999-09-23 09:48:14 -0400
+
+  changes by Arthur David Olson and Paul Eggert
+
+
+Release 1999e - 1999-08-17 15:20:54 -0400
+
+  changes circulated by Paul Eggert, although the change to handling
+  of DST-specifying time zone names has been commented out for now
+  (search for "XXX" in "localtime.c" for details).  These files also
+  do not make any changes to the start of DST in Brazil.
+
+  In addition to Paul's changes, there are updates to "Arts.htm" and
+  cleanups of URLs.
+
+
+Release 1999d - 1999-03-30 11:31:07 -0500
+
+  changes by Paul Eggert
+
+  The Makefile's "make public" rule has also been changed to do a test
+  compile of each individual time zone data file (which should help
+  avoid problems such as the one we had with Nicosia).
+
+
+Release 1999c - 1999-03-25 09:47:47 -0500
+
+  changes by Paul Eggert, most importantly the change for Chile.
+
+
+Release 1999b - 1999-02-01 17:51:44 -0500
+
+  changes by Paul Eggert
+
+  code changes (suggested by Mani Varadarajan, mani at be.com) for
+  correct handling of symbolic links when building using a relative directory
+
+  code changes to generate correct messages for failed links
+
+  updates to the URLs in Arts.htm
+
+
+Release 1999a - 1999-01-19 16:20:29 -0500
+
+  error message internationalizations and corrections in zic.c and
+  zdump.c (as suggested by Vladimir Michl, vladimir.michl at upol.cz,
+  to whom thanks!)
+
+
+Release code1998h-data1998i - 1998-10-01 09:56:10 -0400
+
+  changes for Brazil, Chile, and Germany
+
+  support for use of "24:00" in the input files for the time zone compiler
+
+
+Release code1998g-data1998h - 1998-09-24 10:50:28 -0400
+
+  changes by Paul Eggert
+
+  correction to a define in the "private.h" file
+
+
+Release data1998g - 1998-08-11 03:28:35 -0000
+  [tzdata1998g.tar.gz is missing!]
+
+  Lithuanian change provided by mgedmin at pub.osf.it
+
+  Move creation of the GMT link with Etc/GMT to "etcetera" (from
+  "backward") to ensure that the GMT file is created even where folks
+  don't want the "backward" links (as suggested by Paul Eggert).
+
+
+Release data1998f - 1998-07-20 13:50:00 -0000
+  [tzdata1998f.tar.gz is missing!]
+
+  Update the "leapseconds" file to include the newly-announced
+  insertion at the end of 1998.
+
+
+Release code1998f - 1998-06-01 10:18:31 -0400
+
+  addition to localtime.c by Guy Harris
+
+
+Release 1998e - 1998-05-28 09:56:26 -0400
+
+  The Makefile is changed to produce zoneinfo-posix rather than
+  zoneinfo/posix, and to produce zoneinfo-leaps rather than
+  zoneinfo/right.
+
+  data changes by Paul Eggert
+
+  changes from Guy Harris to provide asctime_r and ctime_r
+
+  A usno1998 file (substantially identical to usno1997) has been added.
+
+
+Release 1998d - 1998-05-14 11:58:34 -0400
+
+  changes to comments (in particular, elimination of references to CIA maps).
+  "Arts.htm", "WWW.htm", "asia", and "australasia" are the only places
+  where changes occur.
+
+
+Release 1998c - 1998-02-28 12:32:26 -0500
+
+  changes by Paul Eggert (save the "French correction," on which I'll
+  wait for the dust to settle)
+
+  symlink changes
+
+  changes and additions to Arts.htm
+
+
+Release 1998b - 1998-01-17 14:31:51 -0500
+
+  URL cleanups and additions
+
+
+Release 1998a - 1998-01-13 12:37:35 -0500
+
+  changes by Paul Eggert
+
+
+Release code1997i-data1997k - 1997-12-29 09:53:41 -0500
+
+  changes by Paul Eggert, with minor modifications from Arthur David
+  Olson to make the files more browser friendly
+
+
+Release code1997h-data1997j - 1997-12-18 17:47:35 -0500
+
+  minor changes to put "TZif" at the start of each time zone information file
+
+  a rule has also been added to the Makefile so you can
+	make zones
+  to just recompile the zone information files (rather than doing a
+  full "make install" with its other effects).
+
+
+Release data1997i - 1997-10-07 08:45:38 -0400
+
+  changes to Africa by Paul Eggert
+
+
+Release code1997g-data1997h - 1997-09-04 16:56:54 -0400
+
+  corrections for Uruguay (and other locations)
+
+  Arthur David Olson's simple-minded fix allowing mktime to both
+  correctly handle leap seconds and correctly handle tm_sec values
+  upon which arithmetic has been performed.
+
+
+Release code1997f-data1997g - 1997-07-19 13:15:02 -0400
+
+  Paul Eggert's updates
+
+  a small change to a function prototype;
+
+  "Music" has been renamed "Arts.htm", HTMLified, and augmented to
+  include information on Around the World in Eighty Days.
+
+
+Release code1997e-data1997f - 1997-05-03 18:52:34 -0400
+
+  fixes to zic's error handling
+
+  changes inspired by the item circulated on Slovenia
+
+  The description of Web resources has been HTMLified for browsing
+  convenience.
+
+  A new piece of tz-related music has been added to the "Music" file.
+
+
+Release code1997d-data1997e - 1997-03-29 12:48:52 -0500
+
+  Paul Eggert's latest suggestions
+
+
+Release code1997c-data1997d - 1997-03-07 20:37:54 -0500
+
+  changes to "zic.c" to correct performance of the "-s" option
+
+  a new file "usno1997"
+
+
+Release data1997c - 1997-03-04 09:58:18 -0500
+
+  changes in Israel
+
+
+Release 1997b - 1997-02-27 18:34:19 -0500
+
+  The data file incorporates the 1997 leap second.
+
+  The code file incorporates Arthur David Olson's take on the
+  zic/multiprocessor/directory-creation situation.
+
+
+Release 1997a - 1997-01-21 09:11:10 -0500
+
+  Paul Eggert's Antarctica (and other changes)
+
+  Arthur David Olson finessed the "getopt" issue by checking against
+  both -1 and EOF (regardless of POSIX, SunOS 4.1.1's manual says -1
+  is returned while SunOS 5.5's manual says EOF is returned).
+
+
+Release code1996o-data1996n - 1996-12-27 21:42:05 -0500
+
+  Paul Eggert's latest changes
+
+
+Release code1996n - 1996-12-16 09:42:02 -0500
+
+  link snapping fix from Bruce Evans (via Garrett Wollman)
+
+
+Release data1996m - 1996-11-24 02:37:34 -0000
+  [tzdata1996m.tar.gz is missing!]
+
+  Paul Eggert's batch of changes
+
+
+Release code1996m-data1996l - 1996-11-05 14:00:12 -0500
+
+  No functional changes here; the files have simply been changed to
+  make more use of ISO style dates in comments. The names of the above
+  files now include the year in full.
+
+
+Release code96l - 1996-09-08 17:12:20 -0400
+
+  tzcode96k was missing a couple of pieces.
+
+
+Release 96k - 1996-09-08 16:06:22 -0400
+
+  the latest round of changes from Paul Eggert
+
+  the recent Year 2000 material
+
+
+Release code96j - 1996-07-30 13:18:53 -0400
+
+  Set sp->typecnt as suggested by Timothy Patrick Murphy.
+
+
+Release code96i - 1996-07-27 20:11:35 -0400
+
+  Paul's suggested patch for strftime %V week numbers
+
+
+Release data96i - 1996-07-01 18:13:04 -0400
+
+  "northamerica" and "europe" changes by Paul Eggert
+
+
+Release code96h - 1996-06-05 08:02:21 -0400
+
+  fix for handling transitions specified in Universal Time
+
+  Some "public domain" notices have also been added.
+
+
+Release code96g - 1996-05-16 14:00:26 -0400
+
+  fix for the simultaneous-DST-and-zone-change challenge
+
+
+Release data96h - 1996-05-09 17:40:51 -0400
+
+  changes by Paul Eggert
+
+
+Release code96f-data96g - 1996-05-03 03:09:59 -0000
+  [tzcode96f.tar.gz + tzdata96g.tar.gz are both missing!]
+
+  The changes get us some of the way to fixing the problems noted in Paul
+  Eggert's letter yesterday (in addition to a few others).  The approach
+  has been to make zic a bit smarter about figuring out what time zone
+  abbreviations apply just after the time specified in the "UNTIL" part
+  of a zone line.  Putting the smarts in zic means avoiding having
+  transition times show up in both "Zone" lines and "Rule" lines, which
+  in turn avoids multiple transition time entries in time zone files.
+  (This also makes the zic input files such as "europe" a bit shorter and
+  should ease maintenance.)
+
+
+Release data96f - 1996-04-19 19:20:03 -0000
+  [tzdata96f.tar.gz is missing!]
+
+  The only changes are to the "northamerica" file; the time zone
+  abbreviation for Denver is corrected to MST (and MDT), and the
+  comments for Mexico have been updated.
+
+
+Release data96e - 1996-03-19 17:37:26 -0500
+
+  Proposals by Paul Eggert, in particular the Portugal change that
+  comes into play at the end of this month.
+
+
+Release data96d - 1996-03-18 20:49:39 -0500
+
+  [not summarized]
+
+
+Release code96e - 1996-02-29 15:43:27 -0000
+  [tzcode96e.tar.gz is missing!]
+
+  internationalization changes and the fix to the documentation for strftime
+
+
+Release code96d-data96c - 1996-02-12 11:05:27 -0500
+
+  The "code" file simply updates Bob Kridle's electronic address.
+
+  The "data" file updates rules for Mexico.
+
+
+Release data96b - 1996-01-27 15:44:42 -0500
+
+  Kiribati change
+
+
+Release code96c - 1996-01-16 16:58:15 -0500
+
+  leap-year streamlining and binary-search changes
+
+  fix to newctime.3
+
+
+Release code96b - 1996-01-10 20:42:39 -0500
+
+  fixes and enhancements from Paul Eggert, including code that
+  emulates the behavior of recent versions of the SunOS "date"
+  command.
+
+
+Release 96a - 1996-01-06 09:08:24 -0500
+
+  Israel updates
+
+  fixes to strftime.c for correct ISO 8601 week number generation,
+  plus support for two new formats ('G' and 'g') to give ISO 8601 year
+  numbers (which are not necessarily the same as calendar year numbers)
+
+
+Release code95i-data95m - 1995-12-21 12:46:47 -0500
+
+  The latest revisions from Paul Eggert are included, the usno1995
+  file has been updated, and a new file ("WWW") covering useful URLs
+  has been added.
+
+
+Release code95h-data95l - 1995-12-19 18:10:12 -0500
+
+  A simplification of a macro definition, a change to data for Sudan,
+  and (for last minute shoppers) notes in the "Music" file on the CD
+  "Old Man Time".
+
+
+Release code95g-data95k - 1995-10-30 10:32:47 -0500
+
+  (slightly reformatted) 8-bit-clean proposed patch
+
+  minor patch: US/Eastern -> America/New_York
+
+  snapshot of the USNO's latest data ("usno1995")
+
+  some other minor cleanups
+
+
+Release code95f-data95j - 1995-10-28 21:01:34 -0000
+  [tzcode95f.tar.gz + tzdata95j.tar.gz are both missing!]
+
+  European cleanups
+
+  support for 64-bit time_t's
+
+  optimization in localtime.c
+
+
+Release code95e - 1995-10-13 13:23:57 -0400
+
+  the mktime change to scan from future to past when trying to find time zone
+  offsets
+
+
+Release data95i - 1995-09-26 10:43:26 -0400
+
+  For Canada/Central, guess that the Sun customer's "one week too
+  early" was just a approximation, and the true error is one month
+  too early.  This is consistent with the rest of Canada.
+
+
+Release data95h - 1995-09-21 11:26:48 -0400
+
+  latest changes from Paul Eggert
+
+
+Release code95d - 1995-09-14 11:14:45 -0400
+
+  the addition of a "Music" file, which documents four recorded
+  versions of the tune "Save That Time".
+
+
+Release data95g - 1995-09-01 17:21:36 -0400
+
+  "yearistype" correction
+
+
+Release data95f - 1995-08-28 20:46:56 -0400
+
+  Paul Eggert's change to the australasia file
+
+
+Release data95e - 1995-07-08 18:02:34 -0400
+
+  The only change is a leap second at the end of this year.
+  Thanks to Bradley White for forwarding news on the leap second.
+
+
+Release data95d - 1995-07-03 13:26:22 -0400
+
+  Paul Eggert's changes
+
+
+Release data95c - 1995-07-02 19:19:28 -0400
+
+  changes to "asia", "backward", "europe", and "southamerica"
+  (read: northamericacentrics need not apply)
+
+
+Release code95c - 1995-03-13 14:00:46 -0500
+
+  one-line fix for sign extension problems in detzcode
+
+
+Release 95b - 1995-03-04 11:22:38 -0500
+
+  Minor changes in both:
+
+  The "code" file contains a workaround for the lack of "unistd.h" in
+  Microsoft C++ version 7.
+
+  The "data" file contains a fixed "Link" for America/Shiprock.
+
+
+Release 94h - 1994-12-10 12:51:14 -0500
+
+  The files:
+
+  *	incorporate the changes to "zdump" and "date" to make changes to
+	the "TZ" environment variable permanent;
+
+  *	incorporate the table changes by Paul Eggert;
+
+  *	include (and document) support for universal time specifications in
+	data files - but do not (yet) include use of this feature in the
+	data files.
+
+  Think of this as "TZ Classic" - the software has been set up not to break if
+  universal time shows up in its input, and data entries have been
+  left as is so as not to break existing implementations.
+
+
+Release data94f - 1994-08-20 12:56:09 -0400
+
+  (with thanks!) the latest data updates from Paul Eggert
+
+
+Release data94e - 1994-06-04 13:13:53 -0400
+
+  [not summarized]
+
+
+Release code94g - 1994-05-05 12:14:07 -0400
+
+  fix missing "optind.c" and a reference to it in the Makefile
+
+
+Release code94f - 1994-05-05 13:00:33 -0000
+  [tzcode94f.tar.gz is missing!]
+
+  changes to avoid overflow in difftime, as well as changes to cope
+  with the 52/53 challenge in strftime
+
+
+Release code94e - 1994-03-30 23:32:59 -0500
+
+  change for the benefit of PCTS
+
+
+Release 94d - 1994-02-24 15:42:25 -0500
+
+  Avoid clashes with POSIX semantics for zones such as GMT+4.
+
+  Some other very minor housekeeping is also present.
+
+
+Release code94c - 1994-02-10 08:52:40 -0500
+
+  Fix bug where mkdirs was broken unless you compile with
+  -fwritable-strings (which is generally losing to do).
+
+
+Release 94b - 1994-02-07 10:04:33 -0500
+
+  work by Paul Eggert who notes:
+
+  I found another book of time zone histories by E W Whitman; it's not
+  as extensive as Shanks but has a few goodies of its own.  I used it
+  to update the tables.  I also fixed some more as a result of
+  correspondence with Adam David and Peter Ilieve, and move some stray
+  links from 'europe' to 'backward'.  I corrected some scanning errors
+  in usno1989.
+
+  As far as the code goes, I fixed zic to allow years in the range
+  INT_MIN to INT_MAX; this fixed a few boundary conditions around 1900.
+  And I cleaned up the zic documentation a little bit.
+
+
+Release data94a - 1994-02-03 08:58:54 -0500
+
+  It simply incorporates the recently announced leap second into the
+  "leapseconds" file.
+
+
+Release 93g - 1993-11-22 17:28:27 -0500
+
+  Paul Eggert has provided a good deal of historic information (based
+  on Shanks), and there are some code changes to deal with the buglets
+  that crawled out in dealing with the new information.
+
+
+Release 93f - 1993-10-15 12:27:46 -0400
+
+  Paul Eggert's changes
+
+
+Release 93e - 1993-09-05 21:21:44 -0400
+
+  This has updated data for Israel, England, and Kwajalein.  There's
+  also an update to "zdump" to cope with Kwajalein's 24-hour jump.
+  Thanks to Paul Eggert and Peter Ilieve for the changes.
+
+
+Release 93d - 1993-06-17 23:34:17 -0400
+
+  new fix and new data on Israel
+
+
+Release 93c - 1993-06-06 19:31:55 -0400
+
+  [not summarized]
+
+
+Release 93b - 1993-02-02 14:53:58 -0500
+
+  updated "leapseconds" file
+
+
+Release 93 - 1993-01-08 07:01:06 -0500
+
+  At kre's suggestion, the package has been split in two - a code piece
+  (which also includes documentation) that's only of use to folks who
+  want to recompile things and a data piece useful to anyone who can
+  run "zic".
+
+  The new version has a few changes to the data files, a few
+  portability changes, and an off-by-one fix (with thanks to
+  Tom Karzes at deshaw.com for providing a description and a
+  solution).
+
+
+Release 92c - 1992-11-21 17:35:36 -0000
+  [tz92c.tar.Z is missing!]
+
+  The fallout from the latest round of DST transitions.
+
+  There are changes for Portugal, Saskatchewan, and "Pacific-New";
+  there's also a change to "zic.c" that makes it portable to more systems.
+
+
+Release 92 - 1992-04-25 18:17:03 -0000
+  [tz92.tar.Z is missing!]
+
+  By popular demand (well, at any rate, following a request by kre at munnari)
+
+
+The 1989 update of the time zone package featured:
+
+  *	POSIXization (including interpretation of POSIX-style TZ environment
+	variables, provided by Guy Harris),
+  *	ANSIfication (including versions of "mktime" and "difftime"),
+  *	SVIDulation (an "altzone" variable)
+  *	MACHination (the "gtime" function)
+  *	corrections to some time zone data (including corrections to the rules
+	for Great Britain and New Zealand)
+  *	reference data from the United States Naval Observatory for folks who
+	want to do additional time zones
+  *	and the 1989 data for Saudi Arabia.
+
+  (Since this code will be treated as "part of the implementation" in some
+  places and as "part of the application" in others, there's no good way to
+  name functions, such as timegm, that are not part of the proposed ANSI C
+  standard; such functions have kept their old, underscore-free names in this
+  update.)
+
+  And the "dysize" function has disappeared; it was present to allow
+  compilation of the "date" command on old BSD systems, and a version of "date"
+  is now provided in the package.  The "date" command is not created when you
+  "make all" since it may lack options provided by the version distributed with
+  your operating system, or may not interact with the system in the same way
+  the native version does.
+
+  Since POSIX frowns on correct leap second handling, the default behavior of
+  the "zic" command (in the absence of a "-L" option) has been changed to omit
+  leap second information from its output files.
+
+
+-----
+Notes
+
+This file contains copies of the part of each release announcement
+that talks about the changes in that release.  The text has been
+adapted and reformatted for the purposes of this file.
+
+Traditionally a release R consists of a pair of tarball files,
+tzcodeR.tar.gz and tzdataR.tar.gz.  However, some releases (e.g.,
+code2010a, data2012c) consist of just one or the other tarball, and a
+few (e.g., code2012c-data2012d) have tarballs with mixed version
+numbers.  Recent releases also come in an experimental format
+consisting of a single tarball tzdb-R.tar.lz with extra data.
+
+Release timestamps are taken from the release's commit (for newer,
+Git-based releases), from the newest file in the tarball (for older
+releases, where this info is available) or from the email announcing
+the release (if all else fails; these are marked with a time zone of
+-0000 and an "is missing!" comment).
+
+Earlier versions of the code and data were not announced on the tz
+list and are not summarized here.
+
+This file is in the public domain.
+
+Local Variables:
+coding: utf-8
+End:
diff --git a/README b/README
new file mode 100644
index 000000000000..ab8e47b63efb
--- /dev/null
+++ b/README
@@ -0,0 +1,52 @@
+README for the tz distribution
+
+"What time is it?" -- Richard Deacon as The King
+"Any time you want it to be." -- Frank Baxter as The Scientist
+					(from the Bell System film "About Time")
+
+The Time Zone Database (often called tz or zoneinfo) contains code and
+data that represent the history of local time for many representative
+locations around the globe.  It is updated periodically to reflect
+changes made by political bodies to time zone boundaries, UTC offsets,
+and daylight-saving rules.
+
+See <https://www.iana.org/time-zones/repository/tz-link.html> or the
+file tz-link.html for how to acquire the code and data.  Once acquired,
+read the comments in the file 'Makefile' and make any changes needed
+to make things right for your system, especially if you are using some
+platform other than GNU/Linux.  Then run the following commands,
+substituting your desired installation directory for "$HOME/tzdir":
+
+	make TOPDIR=$HOME/tzdir install
+	$HOME/tzdir/usr/bin/zdump -v America/Los_Angeles
+
+Historical local time information has been included here to:
+
+*	provide a compendium of data about the history of civil time
+	that is useful even if not 100% accurate;
+
+*	give an idea of the variety of local time rules that have
+	existed in the past and thus an idea of the variety that may be
+	expected in the future;
+
+*	provide a test of the generality of the local time rule description
+	system.
+
+The information in the time zone data files is by no means authoritative;
+fixes and enhancements are welcome.  Please see the file CONTRIBUTING
+for details.
+
+Thanks to these Time Zone Caballeros who've made major contributions to the
+time conversion package: Keith Bostic; Bob Devine; Paul Eggert; Robert Elz;
+Guy Harris; Mark Horton; John Mackin; and Bradley White.  Thanks also to
+Michael Bloom, Art Neilson, Stephen Prince, John Sovereign, and Frank Wales
+for testing work, and to Gwillim Law for checking local mean time data.
+Thanks in particular to Arthur David Olson, the project's founder and first
+maintainer, to whom the time zone community owes the greatest debt of all.
+None of them are responsible for remaining errors.
+
+-----
+
+This file is in the public domain, so clarified as of 2009-05-17 by
+Arthur David Olson.  The other files in this distribution are either
+public domain or BSD licensed; see the file LICENSE for details.
diff --git a/asctime.c b/asctime.c
new file mode 100644
index 000000000000..56c54b383f68
--- /dev/null
+++ b/asctime.c
@@ -0,0 +1,122 @@
+/* asctime and asctime_r a la POSIX and ISO C, except pad years before 1000.  */
+
+/*
+** This file is in the public domain, so clarified as of
+** 1996-06-05 by Arthur David Olson.
+*/
+
+/*
+** Avoid the temptation to punt entirely to strftime;
+** the output of strftime is supposed to be locale specific
+** whereas the output of asctime is supposed to be constant.
+*/
+
+/*LINTLIBRARY*/
+
+#include "private.h"
+#include <stdio.h>
+
+/*
+** Some systems only handle "%.2d"; others only handle "%02d";
+** "%02.2d" makes (most) everybody happy.
+** At least some versions of gcc warn about the %02.2d;
+** we conditionalize below to avoid the warning.
+*/
+/*
+** All years associated with 32-bit time_t values are exactly four digits long;
+** some years associated with 64-bit time_t values are not.
+** Vintage programs are coded for years that are always four digits long
+** and may assume that the newline always lands in the same place.
+** For years that are less than four digits, we pad the output with
+** leading zeroes to get the newline in the traditional place.
+** The -4 ensures that we get four characters of output even if
+** we call a strftime variant that produces fewer characters for some years.
+** The ISO C and POSIX standards prohibit padding the year,
+** but many implementations pad anyway; most likely the standards are buggy.
+*/
+#ifdef __GNUC__
+#define ASCTIME_FMT	"%s %s%3d %2.2d:%2.2d:%2.2d %-4s\n"
+#else /* !defined __GNUC__ */
+#define ASCTIME_FMT	"%s %s%3d %02.2d:%02.2d:%02.2d %-4s\n"
+#endif /* !defined __GNUC__ */
+/*
+** For years that are more than four digits we put extra spaces before the year
+** so that code trying to overwrite the newline won't end up overwriting
+** a digit within a year and truncating the year (operating on the assumption
+** that no output is better than wrong output).
+*/
+#ifdef __GNUC__
+#define ASCTIME_FMT_B	"%s %s%3d %2.2d:%2.2d:%2.2d     %s\n"
+#else /* !defined __GNUC__ */
+#define ASCTIME_FMT_B	"%s %s%3d %02.2d:%02.2d:%02.2d     %s\n"
+#endif /* !defined __GNUC__ */
+
+#define STD_ASCTIME_BUF_SIZE	26
+/*
+** Big enough for something such as
+** ??? ???-2147483648 -2147483648:-2147483648:-2147483648     -2147483648\n
+** (two three-character abbreviations, five strings denoting integers,
+** seven explicit spaces, two explicit colons, a newline,
+** and a trailing NUL byte).
+** The values above are for systems where an int is 32 bits and are provided
+** as an example; the define below calculates the maximum for the system at
+** hand.
+*/
+#define MAX_ASCTIME_BUF_SIZE	(2*3+5*INT_STRLEN_MAXIMUM(int)+7+2+1+1)
+
+static char	buf_asctime[MAX_ASCTIME_BUF_SIZE];
+
+char *
+asctime_r(register const struct tm *timeptr, char *buf)
+{
+	static const char	wday_name[][4] = {
+		"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
+	};
+	static const char	mon_name[][4] = {
+		"Jan", "Feb", "Mar", "Apr", "May", "Jun",
+		"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
+	};
+	register const char *	wn;
+	register const char *	mn;
+	char			year[INT_STRLEN_MAXIMUM(int) + 2];
+	char			result[MAX_ASCTIME_BUF_SIZE];
+
+	if (timeptr == NULL) {
+		errno = EINVAL;
+		return strcpy(buf, "??? ??? ?? ??:??:?? ????\n");
+	}
+	if (timeptr->tm_wday < 0 || timeptr->tm_wday >= DAYSPERWEEK)
+		wn = "???";
+	else	wn = wday_name[timeptr->tm_wday];
+	if (timeptr->tm_mon < 0 || timeptr->tm_mon >= MONSPERYEAR)
+		mn = "???";
+	else	mn = mon_name[timeptr->tm_mon];
+	/*
+	** Use strftime's %Y to generate the year, to avoid overflow problems
+	** when computing timeptr->tm_year + TM_YEAR_BASE.
+	** Assume that strftime is unaffected by other out-of-range members
+	** (e.g., timeptr->tm_mday) when processing "%Y".
+	*/
+	strftime(year, sizeof year, "%Y", timeptr);
+	/*
+	** We avoid using snprintf since it's not available on all systems.
+	*/
+	sprintf(result,
+		((strlen(year) <= 4) ? ASCTIME_FMT : ASCTIME_FMT_B),
+		wn, mn,
+		timeptr->tm_mday, timeptr->tm_hour,
+		timeptr->tm_min, timeptr->tm_sec,
+		year);
+	if (strlen(result) < STD_ASCTIME_BUF_SIZE || buf == buf_asctime)
+		return strcpy(buf, result);
+	else {
+		errno = EOVERFLOW;
+		return NULL;
+	}
+}
+
+char *
+asctime(register const struct tm *timeptr)
+{
+	return asctime_r(timeptr, buf_asctime);
+}
diff --git a/calendars b/calendars
new file mode 100644
index 000000000000..8bc70626eb5a
--- /dev/null
+++ b/calendars
@@ -0,0 +1,173 @@
+----- Calendrical issues -----
+
+As mentioned in Theory.html, although calendrical issues are out of
+scope for tzdb, they indicate the sort of problems that we would run
+into if we extended tzdb further into the past.  The following
+information and sources go beyond Theory.html's brief discussion.
+They sometimes disagree.
+
+
+France
+
+Gregorian calendar adopted 1582-12-20.
+French Revolutionary calendar used 1793-11-24 through 1805-12-31,
+and (in Paris only) 1871-05-06 through 1871-05-23.
+
+
+Russia
+
+From Chris Carrier (1996-12-02):
+On 1929-10-01 the Soviet Union instituted an "Eternal Calendar"
+with 30-day months plus 5 holidays, with a 5-day week.
+On 1931-12-01 it changed to a 6-day week; in 1934 it reverted to the
+Gregorian calendar while retaining the 6-day week; on 1940-06-27 it
+reverted to the 7-day week.  With the 6-day week the usual days
+off were the 6th, 12th, 18th, 24th and 30th of the month.
+(Source: Evitiar Zerubavel, _The Seven Day Circle_)
+
+
+Mark Brader reported a similar story in "The Book of Calendars", edited
+by Frank Parise (1982, Facts on File, ISBN 0-8719-6467-8), page 377.  But:
+
+From: Petteri Sulonen (via Usenet)
+Date: 14 Jan 1999 00:00:00 GMT
+...
+
+If your source is correct, how come documents between 1929 and 1940 were
+still dated using the conventional, Gregorian calendar?
+
+I can post a scan of a document dated December 1, 1934, signed by
+Yenukidze, the secretary, on behalf of Kalinin, the President of the
+Executive Committee of the Supreme Soviet, if you like.
+
+
+
+Sweden (and Finland)
+
+From: Mark Brader
+Subject: Re: Gregorian reform - a part of locale?
+<news:1996Jul6.012937.29190@sq.com>
+Date: 1996-07-06
+
+In 1700, Denmark made the transition from Julian to Gregorian.  Sweden
+decided to *start* a transition in 1700 as well, but rather than have one of
+those unsightly calendar gaps :-), they simply decreed that the next leap
+year after 1696 would be in 1744 - putting the whole country on a calendar
+different from both Julian and Gregorian for a period of 40 years.
+
+However, in 1704 something went wrong and the plan was not carried through;
+they did, after all, have a leap year that year.  And one in 1708.  In 1712
+they gave it up and went back to Julian, putting 30 days in February that
+year!...
+
+Then in 1753, Sweden made the transition to Gregorian in the usual manner,
+getting there only 13 years behind the original schedule.
+
+(A previous posting of this story was challenged, and Swedish readers
+produced the following references to support it: "Tideräkning och historia"
+by Natanael Beckman (1924) and "Tid, en bok om tideräkning och
+kalenderväsen" by Lars-Olof Lodén (1968).
+
+
+Grotefend's data
+
+From: "Michael Palmer" [with one obvious typo fixed]
+Subject: Re: Gregorian Calendar (was Re: Another FHC related question
+Newsgroups: soc.genealogy.german
+Date: Tue, 9 Feb 1999 02:32:48 -800
+...
+
+The following is a(n incomplete) listing, arranged chronologically, of
+European states, with the date they converted from the Julian to the
+Gregorian calendar:
+
+04/15 Oct 1582 - Italy (with exceptions), Spain, Portugal, Poland (Roman
+                 Catholics and Danzig only)
+09/20 Dec 1582 - France, Lorraine
+
+21 Dec 1582/
+   01 Jan 1583 - Holland, Brabant, Flanders, Hennegau
+10/21 Feb 1583 - bishopric of Liege (Lüttich)
+13/24 Feb 1583 - bishopric of Augsburg
+04/15 Oct 1583 - electorate of Trier
+05/16 Oct 1583 - Bavaria, bishoprics of Freising, Eichstedt, Regensburg,
+                 Salzburg, Brixen
+13/24 Oct 1583 - Austrian Oberelsaß and Breisgau
+20/31 Oct 1583 - bishopric of Basel
+02/13 Nov 1583 - duchy of Jülich-Berg
+02/13 Nov 1583 - electorate and city of Köln
+04/15 Nov 1583 - bishopric of Würzburg
+11/22 Nov 1583 - electorate of Mainz
+16/27 Nov 1583 - bishopric of Strassburg and the margraviate of Baden
+17/28 Nov 1583 - bishopric of Münster and duchy of Cleve
+14/25 Dec 1583 - Steiermark
+
+06/17 Jan 1584 - Austria and Bohemia
+11/22 Jan 1584 - Lucerne, Uri, Schwyz, Zug, Freiburg, Solothurn
+12/23 Jan 1584 - Silesia and the Lausitz
+22 Jan/
+   02 Feb 1584 - Hungary (legally on 21 Oct 1587)
+      Jun 1584 - Unterwalden
+01/12 Jul 1584 - duchy of Westfalen
+
+16/27 Jun 1585 - bishopric of Paderborn
+
+14/25 Dec 1590 - Transylvania
+
+22 Aug/
+   02 Sep 1612 - duchy of Prussia
+
+13/24 Dec 1614 - Pfalz-Neuburg
+
+          1617 - duchy of Kurland (reverted to the Julian calendar in
+                 1796)
+
+          1624 - bishopric of Osnabrück
+
+          1630 - bishopric of Minden
+
+15/26 Mar 1631 - bishopric of Hildesheim
+
+          1655 - Kanton Wallis
+
+05/16 Feb 1682 - city of Strassburg
+
+18 Feb/
+   01 Mar 1700 - Protestant Germany (including Swedish possessions in
+                 Germany), Denmark, Norway
+30 Jun/
+   12 Jul 1700 - Gelderland, Zutphen
+10 Nov/
+   12 Dec 1700 - Utrecht, Overijssel
+
+31 Dec 1700/
+   12 Jan 1701 - Friesland, Groningen, Zürich, Bern, Basel, Geneva,
+                 Turgau, and Schaffhausen
+
+          1724 - Glarus, Appenzell, and the city of St. Gallen
+
+01 Jan 1750    - Pisa and Florence
+
+02/14 Sep 1752 - Great Britain
+
+17 Feb/
+   01 Mar 1753 - Sweden
+
+1760-1812      - Graubünden
+
+The Russian empire (including Finland and the Baltic states) did not
+convert to the Gregorian calendar until the Soviet revolution of 1917.
+
+Source: H. Grotefend, _Taschenbuch der Zeitrechnung des deutschen
+Mittelalters und der Neuzeit_, herausgegeben von Dr. O. Grotefend
+(Hannover: Hahnsche Buchhandlung, 1941), pp. 26-28.
+
+-----
+
+This file is in the public domain, so clarified as of 2009-05-17 by
+Arthur David Olson.
+
+-----
+Local Variables:
+coding: utf-8
+End:
diff --git a/date.1 b/date.1
new file mode 100644
index 000000000000..28dc1d7c08a4
--- /dev/null
+++ b/date.1
@@ -0,0 +1,165 @@
+.TH DATE 1
+.SH NAME
+date \- show and set date and time
+.SH SYNOPSIS
+.if n .nh
+.if n .na
+.ie \n(.g .ds - \f(CW-\fP
+.el ds - \-
+.B date
+[
+.B \*-u
+] [
+.B \*-c
+] [
+.B \*-r
+.I seconds
+] [
+.BI + format
+] [
+\fR[\fIyyyy\fR]\fImmddhhmm\fR[\fIyy\fR][\fB.\fIss\fR]
+]
+.SH DESCRIPTION
+.ie '\(lq'' .ds lq \&"\"
+.el .ds lq \(lq\"
+.ie '\(rq'' .ds rq \&"\"
+.el .ds rq \(rq\"
+.de q
+\\$3\*(lq\\$1\*(rq\\$2
+..
+.I Date
+without arguments writes the date and time to the standard output in
+the form
+.ce 1
+Wed Mar  8 14:54:40 EST 1989
+.br
+with
+.B EST
+replaced by the local time zone's abbreviation
+(or by the abbreviation for the time zone specified in the
+.B TZ
+environment variable if set).
+The exact output format depends on the locale.
+.PP
+If a command-line argument starts with a plus sign (\c
+.q "\fB+\fP" ),
+the rest of the argument is used as a
+.I format
+that controls what appears in the output.
+In the format, when a percent sign (\c
+.q "\fB%\fP"
+appears,
+it and the character after it are not output,
+but rather identify part of the date or time
+to be output in a particular way
+(or identify a special character to output):
+.nf
+.sp
+.if t .in +.5i
+.if n .in +2
+.ta \w'%M\0\0'u +\w'Wed Mar  8 14:54:40 EST 1989\0\0'u
+	Sample output	Explanation
+%a	Wed	Abbreviated weekday name*
+%A	Wednesday	Full weekday name*
+%b	Mar	Abbreviated month name*
+%B	March	Full month name*
+%c	Wed Mar 08 14:54:40 1989	Date and time*
+%C	19	Century
+%d	08	Day of month (always two digits)
+%D	03/08/89	Month/day/year (eight characters)
+%e	 8	Day of month (leading zero blanked)
+%h	Mar	Abbreviated month name*
+%H	14	24-hour-clock hour (two digits)
+%I	02	12-hour-clock hour (two digits)
+%j	067	Julian day number (three digits)
+%k	 2	12-hour-clock hour (leading zero blanked)
+%l	14	24-hour-clock hour (leading zero blanked)
+%m	03	Month number (two digits)
+%M	54	Minute (two digits)
+%n	\\n	newline character
+%p	PM	AM/PM designation
+%r	02:54:40 PM	Hour:minute:second AM/PM designation
+%R	14:54	Hour:minute
+%S	40	Second (two digits)
+%t	\\t	tab character
+%T	14:54:40	Hour:minute:second
+%U	10	Sunday-based week number (two digits)
+%w	3	Day number (one digit, Sunday is 0)
+%W	10	Monday-based week number (two digits)
+%x	03/08/89	Date*
+%X	14:54:40	Time*
+%y	89	Last two digits of year
+%Y	1989	Year in full
+%z	-0500	Numeric time zone
+%Z	EST	Time zone abbreviation
+%+	Wed Mar  8 14:54:40 EST 1989	Default output format*
+.if t .in -.5i
+.if n .in -2
+* The exact output depends on the locale.
+.sp
+.fi
+If a character other than one of those shown above appears after
+a percent sign in the format,
+that following character is output.
+All other characters in the format are copied unchanged to the output;
+a newline character is always added at the end of the output.
+.PP
+In Sunday-based week numbering,
+the first Sunday of the year begins week 1;
+days preceding it are part of
+.q "week 0" .
+In Monday-based week numbering,
+the first Monday of the year begins week 1.
+.PP
+To set the date, use a command line argument with one of the following forms:
+.nf
+.if t .in +.5i
+.if n .in +2
+.ta \w'198903081454\0'u
+1454	24-hour-clock hours (first two digits) and minutes
+081454	Month day (first two digits), hours, and minutes
+03081454	Month (two digits, January is 01), month day, hours, minutes
+8903081454	Year, month, month day, hours, minutes
+0308145489	Month, month day, hours, minutes, year
+	(on System V-compatible systems)
+030814541989	Month, month day, hours, minutes, four-digit year
+198903081454	Four-digit year, month, month day, hours, minutes
+.if t .in -.5i
+.if n .in -2
+.fi
+If the century, year, month, or month day is not given,
+the current value is used.
+Any of the above forms may be followed by a period and two digits that give
+the seconds part of the new time; if no seconds are given, zero is assumed.
+.PP
+These options are available:
+.TP
+.BR \*-u " or " \*-c
+Use Universal Time when setting and showing the date and time.
+.TP
+.BI "\*-r " seconds
+Output the date that corresponds to
+.I seconds
+past the epoch of 1970-01-01 00:00:00 UTC, where
+.I seconds
+should be an integer, either decimal, octal (leading 0), or
+hexadecimal (leading 0x), preceded by an optional sign.
+.SH FILES
+.ta \w'/usr/share/zoneinfo/posixrules\0\0'u
+/etc/localtime	local time zone file
+.br
+/usr/lib/locale/\f2L\fP/LC_TIME	description of time locale \f2L\fP
+.br
+/usr/share/zoneinfo	time zone information directory
+.br
+/usr/share/zoneinfo/posixrules	used with POSIX-style TZ's
+.br
+/usr/share/zoneinfo/GMT	for UTC leap seconds
+.sp
+If
+.B /usr/share/zoneinfo/GMT
+is absent,
+UTC leap seconds are loaded from
+.BR /usr/share/zoneinfo/posixrules .
+.\" This file is in the public domain, so clarified as of
+.\" 2009-05-17 by Arthur David Olson.
diff --git a/date.1.txt b/date.1.txt
new file mode 100644
index 000000000000..de500a347081
--- /dev/null
+++ b/date.1.txt
@@ -0,0 +1,107 @@
+DATE(1)                     General Commands Manual                    DATE(1)
+
+NAME
+       date - show and set date and time
+
+SYNOPSIS
+       date [ -u ] [ -c ] [ -r seconds ] [ +format ] [ [yyyy]mmddhhmm[yy][.ss]
+       ]
+
+DESCRIPTION
+       Date without arguments writes the date and time to the standard output
+       in the form
+                            Wed Mar  8 14:54:40 EST 1989
+       with EST replaced by the local time zone's abbreviation (or by the
+       abbreviation for the time zone specified in the TZ environment variable
+       if set).  The exact output format depends on the locale.
+
+       If a command-line argument starts with a plus sign ("+"), the rest of
+       the argument is used as a format that controls what appears in the
+       output.  In the format, when a percent sign ("%" appears, it and the
+       character after it are not output, but rather identify part of the date
+       or time to be output in a particular way (or identify a special
+       character to output):
+
+             Sample output                 Explanation
+         %a  Wed                           Abbreviated weekday name*
+         %A  Wednesday                     Full weekday name*
+         %b  Mar                           Abbreviated month name*
+         %B  March                         Full month name*
+         %c  Wed Mar 08 14:54:40 1989      Date and time*
+         %C  19                            Century
+         %d  08                            Day of month (always two digits)
+         %D  03/08/89                      Month/day/year (eight characters)
+         %e   8                            Day of month (leading zero blanked)
+         %h  Mar                           Abbreviated month name*
+         %H  14                            24-hour-clock hour (two digits)
+         %I  02                            12-hour-clock hour (two digits)
+         %j  067                           Julian day number (three digits)
+         %k   2                            12-hour-clock hour (leading zero blanked)
+         %l  14                            24-hour-clock hour (leading zero blanked)
+         %m  03                            Month number (two digits)
+         %M  54                            Minute (two digits)
+         %n  \n                            newline character
+         %p  PM                            AM/PM designation
+         %r  02:54:40 PM                   Hour:minute:second AM/PM designation
+         %R  14:54                         Hour:minute
+         %S  40                            Second (two digits)
+         %t  \t                            tab character
+         %T  14:54:40                      Hour:minute:second
+         %U  10                            Sunday-based week number (two digits)
+         %w  3                             Day number (one digit, Sunday is 0)
+         %W  10                            Monday-based week number (two digits)
+         %x  03/08/89                      Date*
+         %X  14:54:40                      Time*
+         %y  89                            Last two digits of year
+         %Y  1989                          Year in full
+         %z  -0500                         Numeric time zone
+         %Z  EST                           Time zone abbreviation
+         %+  Wed Mar  8 14:54:40 EST 1989  Default output format*
+       * The exact output depends on the locale.
+
+       If a character other than one of those shown above appears after a
+       percent sign in the format, that following character is output.  All
+       other characters in the format are copied unchanged to the output; a
+       newline character is always added at the end of the output.
+
+       In Sunday-based week numbering, the first Sunday of the year begins
+       week 1; days preceding it are part of "week 0".  In Monday-based week
+       numbering, the first Monday of the year begins week 1.
+
+       To set the date, use a command line argument with one of the following
+       forms:
+         1454         24-hour-clock hours (first two digits) and minutes
+         081454       Month day (first two digits), hours, and minutes
+         03081454     Month (two digits, January is 01), month day, hours, minutes
+         8903081454   Year, month, month day, hours, minutes
+         0308145489   Month, month day, hours, minutes, year
+                      (on System V-compatible systems)
+         030814541989 Month, month day, hours, minutes, four-digit year
+         198903081454 Four-digit year, month, month day, hours, minutes
+       If the century, year, month, or month day is not given, the current
+       value is used.  Any of the above forms may be followed by a period and
+       two digits that give the seconds part of the new time; if no seconds
+       are given, zero is assumed.
+
+       These options are available:
+
+       -u or -c
+              Use Universal Time when setting and showing the date and time.
+
+       -r seconds
+              Output the date that corresponds to seconds past the epoch of
+              1970-01-01 00:00:00 UTC, where seconds should be an integer,
+              either decimal, octal (leading 0), or hexadecimal (leading 0x),
+              preceded by an optional sign.
+
+FILES
+       /etc/localtime                  local time zone file
+       /usr/lib/locale/L/LC_TIME       description of time locale L
+       /usr/share/zoneinfo             time zone information directory
+       /usr/share/zoneinfo/posixrules  used with POSIX-style TZ's
+       /usr/share/zoneinfo/GMT         for UTC leap seconds
+
+       If /usr/share/zoneinfo/GMT is absent, UTC leap seconds are loaded from
+       /usr/share/zoneinfo/posixrules.
+
+                                                                       DATE(1)
diff --git a/date.c b/date.c
new file mode 100644
index 000000000000..2cc533fdd4d2
--- /dev/null
+++ b/date.c
@@ -0,0 +1,237 @@
+/* Display or set the current time and date.  */
+
+/* Copyright 1985, 1987, 1988 The Regents of the University of California.
+   All rights reserved.
+
+   Redistribution and use in source and binary forms, with or without
+   modification, are permitted provided that the following conditions
+   are met:
+   1. Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+   2. Redistributions in binary form must reproduce the above copyright
+      notice, this list of conditions and the following disclaimer in the
+      documentation and/or other materials provided with the distribution.
+   3. Neither the name of the University nor the names of its contributors
+      may be used to endorse or promote products derived from this software
+      without specific prior written permission.
+
+   THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS" AND
+   ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+   IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+   ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+   FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+   DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+   OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+   HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+   LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+   OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+   SUCH DAMAGE.  */
+
+#include "private.h"
+#include <locale.h>
+#include <stdio.h>
+
+/*
+** The two things date knows about time are. . .
+*/
+
+#ifndef TM_YEAR_BASE
+#define TM_YEAR_BASE	1900
+#endif /* !defined TM_YEAR_BASE */
+
+#ifndef SECSPERMIN
+#define SECSPERMIN	60
+#endif /* !defined SECSPERMIN */
+
+#if !HAVE_POSIX_DECLS
+extern char *		optarg;
+extern int		optind;
+#endif
+
+static int		retval = EXIT_SUCCESS;
+
+static void		display(const char *, time_t);
+static void		dogmt(void);
+static void		errensure(void);
+static void		timeout(FILE *, const char *, const struct tm *);
+static _Noreturn void	usage(void);
+
+int
+main(const int argc, char *argv[])
+{
+	register const char *	format;
+	register const char *	cp;
+	register int		ch;
+	register bool		rflag = false;
+	time_t			t;
+	intmax_t		secs;
+	char *			endarg;
+
+#ifdef LC_ALL
+	setlocale(LC_ALL, "");
+#endif /* defined(LC_ALL) */
+#if HAVE_GETTEXT
+#ifdef TZ_DOMAINDIR
+	bindtextdomain(TZ_DOMAIN, TZ_DOMAINDIR);
+#endif /* defined(TEXTDOMAINDIR) */
+	textdomain(TZ_DOMAIN);
+#endif /* HAVE_GETTEXT */
+	t = time(NULL);
+	format = NULL;
+	while ((ch = getopt(argc, argv, "ucr:")) != EOF && ch != -1) {
+		switch (ch) {
+		default:
+			usage();
+		case 'u':		/* do it in UT */
+		case 'c':
+			dogmt();
+			break;
+		case 'r':		/* seconds since 1970 */
+			if (rflag) {
+				fprintf(stderr,
+					_("date: error: multiple -r's used"));
+				usage();
+			}
+			rflag = true;
+			errno = 0;
+			secs = strtoimax (optarg, &endarg, 0);
+			if (*endarg || optarg == endarg)
+				errno = EINVAL;
+			else if (! (TIME_T_MIN <= secs && secs <= TIME_T_MAX))
+				errno = ERANGE;
+			if (errno) {
+				perror(optarg);
+				errensure();
+				exit(retval);
+			}
+			t = secs;
+			break;
+		}
+	}
+	while (optind < argc) {
+		cp = argv[optind++];
+		if (*cp == '+')
+			if (format == NULL)
+				format = cp + 1;
+			else {
+				fprintf(stderr,
+_("date: error: multiple formats in command line\n"));
+				usage();
+			}
+		else {
+		  fprintf(stderr, _("date: unknown operand: %s\n"), cp);
+		  usage();
+		}
+	}
+
+	display(format, t);
+	return retval;
+}
+
+static void
+dogmt(void)
+{
+	static char **	fakeenv;
+
+	if (fakeenv == NULL) {
+		register int	from;
+		register int	to;
+		register int	n;
+		static char	tzegmt0[] = "TZ=GMT0";
+
+		for (n = 0;  environ[n] != NULL;  ++n)
+			continue;
+		fakeenv = malloc((n + 2) * sizeof *fakeenv);
+		if (fakeenv == NULL) {
+			perror(_("Memory exhausted"));
+			errensure();
+			exit(retval);
+		}
+		to = 0;
+		fakeenv[to++] = tzegmt0;
+		for (from = 1; environ[from] != NULL; ++from)
+			if (strncmp(environ[from], "TZ=", 3) != 0)
+				fakeenv[to++] = environ[from];
+		fakeenv[to] = NULL;
+		environ = fakeenv;
+	}
+}
+
+static void
+errensure(void)
+{
+	if (retval == EXIT_SUCCESS)
+		retval = EXIT_FAILURE;
+}
+
+static void
+usage(void)
+{
+	fprintf(stderr,
+		       _("date: usage: date [-u] [-c] [-r seconds]"
+			 " [+format]\n"));
+	errensure();
+	exit(retval);
+}
+
+static void
+display(char const *format, time_t now)
+{
+	struct tm *tmp;
+
+	tmp = localtime(&now);
+	if (!tmp) {
+		fprintf(stderr,
+			_("date: error: time out of range\n"));
+		errensure();
+		return;
+	}
+	timeout(stdout, format ? format : "%+", tmp);
+	putchar('\n');
+	fflush(stdout);
+	fflush(stderr);
+	if (ferror(stdout) || ferror(stderr)) {
+		fprintf(stderr,
+			_("date: error: couldn't write results\n"));
+		errensure();
+	}
+}
+
+#define INCR	1024
+
+static void
+timeout(FILE *fp, char const *format, struct tm const *tmp)
+{
+	char *	cp;
+	size_t	result;
+	size_t	size;
+	struct tm tm;
+
+	if (*format == '\0')
+		return;
+	if (!tmp) {
+		fprintf(stderr, _("date: error: time out of range\n"));
+		errensure();
+		return;
+	}
+	tm = *tmp;
+	tmp = &tm;
+	size = INCR;
+	cp = malloc(size);
+	for ( ; ; ) {
+		if (cp == NULL) {
+			fprintf(stderr,
+				_("date: error: can't get memory\n"));
+			errensure();
+			exit(retval);
+		}
+		cp[0] = '\1';
+		result = strftime(cp, size, format, tmp);
+		if (result != 0 || cp[0] == '\0')
+			break;
+		size += INCR;
+		cp = realloc(cp, size);
+	}
+	fwrite(cp, 1, result, fp);
+	free(cp);
+}
diff --git a/difftime.c b/difftime.c
new file mode 100644
index 000000000000..856234a90d0b
--- /dev/null
+++ b/difftime.c
@@ -0,0 +1,58 @@
+/*
+** This file is in the public domain, so clarified as of
+** 1996-06-05 by Arthur David Olson.
+*/
+
+/*LINTLIBRARY*/
+
+#include "private.h"	/* for time_t and TYPE_SIGNED */
+
+/* Return -X as a double.  Using this avoids casting to 'double'.  */
+static double
+dminus(double x)
+{
+  return -x;
+}
+
+double
+difftime(time_t time1, time_t time0)
+{
+	/*
+	** If double is large enough, simply convert and subtract
+	** (assuming that the larger type has more precision).
+	*/
+	if (sizeof (time_t) < sizeof (double)) {
+	  double t1 = time1, t0 = time0;
+	  return t1 - t0;
+	}
+
+	/*
+	** The difference of two unsigned values can't overflow
+	** if the minuend is greater than or equal to the subtrahend.
+	*/
+	if (!TYPE_SIGNED(time_t))
+	  return time0 <= time1 ? time1 - time0 : dminus(time0 - time1);
+
+	/* Use uintmax_t if wide enough.  */
+	if (sizeof (time_t) <= sizeof (uintmax_t)) {
+	  uintmax_t t1 = time1, t0 = time0;
+	  return time0 <= time1 ? t1 - t0 : dminus(t0 - t1);
+	}
+
+	/*
+	** Handle cases where both time1 and time0 have the same sign
+	** (meaning that their difference cannot overflow).
+	*/
+	if ((time1 < 0) == (time0 < 0))
+	  return time1 - time0;
+
+	/*
+	** The values have opposite signs and uintmax_t is too narrow.
+	** This suffers from double rounding; attempt to lessen that
+	** by using long double temporaries.
+	*/
+	{
+	  long double t1 = time1, t0 = time0;
+	  return t1 - t0;
+	}
+}
diff --git a/localtime.c b/localtime.c
new file mode 100644
index 000000000000..5b5a5b131b36
--- /dev/null
+++ b/localtime.c
@@ -0,0 +1,2342 @@
+/*
+** This file is in the public domain, so clarified as of
+** 1996-06-05 by Arthur David Olson.
+*/
+
+/*
+** Leap second handling from Bradley White.
+** POSIX-style TZ environment variable handling from Guy Harris.
+*/
+
+/*LINTLIBRARY*/
+
+#define LOCALTIME_IMPLEMENTATION
+#include "private.h"
+
+#include "tzfile.h"
+#include <fcntl.h>
+
+#if defined THREAD_SAFE && THREAD_SAFE
+# include <pthread.h>
+static pthread_mutex_t locallock = PTHREAD_MUTEX_INITIALIZER;
+static int lock(void) { return pthread_mutex_lock(&locallock); }
+static void unlock(void) { pthread_mutex_unlock(&locallock); }
+#else
+static int lock(void) { return 0; }
+static void unlock(void) { }
+#endif
+
+/* NETBSD_INSPIRED_EXTERN functions are exported to callers if
+   NETBSD_INSPIRED is defined, and are private otherwise.  */
+#if NETBSD_INSPIRED
+# define NETBSD_INSPIRED_EXTERN
+#else
+# define NETBSD_INSPIRED_EXTERN static
+#endif
+
+#ifndef TZ_ABBR_MAX_LEN
+#define TZ_ABBR_MAX_LEN	16
+#endif /* !defined TZ_ABBR_MAX_LEN */
+
+#ifndef TZ_ABBR_CHAR_SET
+#define TZ_ABBR_CHAR_SET \
+	"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789 :+-._"
+#endif /* !defined TZ_ABBR_CHAR_SET */
+
+#ifndef TZ_ABBR_ERR_CHAR
+#define TZ_ABBR_ERR_CHAR	'_'
+#endif /* !defined TZ_ABBR_ERR_CHAR */
+
+/*
+** SunOS 4.1.1 headers lack O_BINARY.
+*/
+
+#ifdef O_BINARY
+#define OPEN_MODE	(O_RDONLY | O_BINARY)
+#endif /* defined O_BINARY */
+#ifndef O_BINARY
+#define OPEN_MODE	O_RDONLY
+#endif /* !defined O_BINARY */
+
+#ifndef WILDABBR
+/*
+** Someone might make incorrect use of a time zone abbreviation:
+**	1.	They might reference tzname[0] before calling tzset (explicitly
+**		or implicitly).
+**	2.	They might reference tzname[1] before calling tzset (explicitly
+**		or implicitly).
+**	3.	They might reference tzname[1] after setting to a time zone
+**		in which Daylight Saving Time is never observed.
+**	4.	They might reference tzname[0] after setting to a time zone
+**		in which Standard Time is never observed.
+**	5.	They might reference tm.TM_ZONE after calling offtime.
+** What's best to do in the above cases is open to debate;
+** for now, we just set things up so that in any of the five cases
+** WILDABBR is used. Another possibility: initialize tzname[0] to the
+** string "tzname[0] used before set", and similarly for the other cases.
+** And another: initialize tzname[0] to "ERA", with an explanation in the
+** manual page of what this "time zone abbreviation" means (doing this so
+** that tzname[0] has the "normal" length of three characters).
+*/
+#define WILDABBR	"   "
+#endif /* !defined WILDABBR */
+
+static const char	wildabbr[] = WILDABBR;
+
+static const char	gmt[] = "GMT";
+
+/*
+** The DST rules to use if TZ has no rules and we can't load TZDEFRULES.
+** Default to US rules as of 2017-05-07.
+** POSIX does not specify the default DST rules;
+** for historical reasons, US rules are a common default.
+*/
+#ifndef TZDEFRULESTRING
+#define TZDEFRULESTRING ",M3.2.0,M11.1.0"
+#endif
+
+struct ttinfo {				/* time type information */
+	int_fast32_t	tt_gmtoff;	/* UT offset in seconds */
+	bool		tt_isdst;	/* used to set tm_isdst */
+	int		tt_abbrind;	/* abbreviation list index */
+	bool		tt_ttisstd;	/* transition is std time */
+	bool		tt_ttisgmt;	/* transition is UT */
+};
+
+struct lsinfo {				/* leap second information */
+	time_t		ls_trans;	/* transition time */
+	int_fast64_t	ls_corr;	/* correction to apply */
+};
+
+#define SMALLEST(a, b)	(((a) < (b)) ? (a) : (b))
+#define BIGGEST(a, b)	(((a) > (b)) ? (a) : (b))
+
+#ifdef TZNAME_MAX
+#define MY_TZNAME_MAX	TZNAME_MAX
+#endif /* defined TZNAME_MAX */
+#ifndef TZNAME_MAX
+#define MY_TZNAME_MAX	255
+#endif /* !defined TZNAME_MAX */
+
+struct state {
+	int		leapcnt;
+	int		timecnt;
+	int		typecnt;
+	int		charcnt;
+	bool		goback;
+	bool		goahead;
+	time_t		ats[TZ_MAX_TIMES];
+	unsigned char	types[TZ_MAX_TIMES];
+	struct ttinfo	ttis[TZ_MAX_TYPES];
+	char		chars[BIGGEST(BIGGEST(TZ_MAX_CHARS + 1, sizeof gmt),
+				(2 * (MY_TZNAME_MAX + 1)))];
+	struct lsinfo	lsis[TZ_MAX_LEAPS];
+	int		defaulttype; /* for early times or if no transitions */
+};
+
+enum r_type {
+  JULIAN_DAY,		/* Jn = Julian day */
+  DAY_OF_YEAR,		/* n = day of year */
+  MONTH_NTH_DAY_OF_WEEK	/* Mm.n.d = month, week, day of week */
+};
+
+struct rule {
+	enum r_type	r_type;		/* type of rule */
+	int		r_day;		/* day number of rule */
+	int		r_week;		/* week number of rule */
+	int		r_mon;		/* month number of rule */
+	int_fast32_t	r_time;		/* transition time of rule */
+};
+
+static struct tm *gmtsub(struct state const *, time_t const *, int_fast32_t,
+			 struct tm *);
+static bool increment_overflow(int *, int);
+static bool increment_overflow_time(time_t *, int_fast32_t);
+static bool normalize_overflow32(int_fast32_t *, int *, int);
+static struct tm *timesub(time_t const *, int_fast32_t, struct state const *,
+			  struct tm *);
+static bool typesequiv(struct state const *, int, int);
+static bool tzparse(char const *, struct state *, bool);
+
+#ifdef ALL_STATE
+static struct state *	lclptr;
+static struct state *	gmtptr;
+#endif /* defined ALL_STATE */
+
+#ifndef ALL_STATE
+static struct state	lclmem;
+static struct state	gmtmem;
+#define lclptr		(&lclmem)
+#define gmtptr		(&gmtmem)
+#endif /* State Farm */
+
+#ifndef TZ_STRLEN_MAX
+#define TZ_STRLEN_MAX 255
+#endif /* !defined TZ_STRLEN_MAX */
+
+static char		lcl_TZname[TZ_STRLEN_MAX + 1];
+static int		lcl_is_set;
+
+/*
+** Section 4.12.3 of X3.159-1989 requires that
+**	Except for the strftime function, these functions [asctime,
+**	ctime, gmtime, localtime] return values in one of two static
+**	objects: a broken-down time structure and an array of char.
+** Thanks to Paul Eggert for noting this.
+*/
+
+static struct tm	tm;
+
+#if !HAVE_POSIX_DECLS || TZ_TIME_T
+# if HAVE_TZNAME
+char *			tzname[2] = {
+	(char *) wildabbr,
+	(char *) wildabbr
+};
+# endif
+# if USG_COMPAT
+long			timezone;
+int			daylight;
+# endif
+# ifdef ALTZONE
+long			altzone;
+# endif
+#endif
+
+/* Initialize *S to a value based on GMTOFF, ISDST, and ABBRIND.  */
+static void
+init_ttinfo(struct ttinfo *s, int_fast32_t gmtoff, bool isdst, int abbrind)
+{
+  s->tt_gmtoff = gmtoff;
+  s->tt_isdst = isdst;
+  s->tt_abbrind = abbrind;
+  s->tt_ttisstd = false;
+  s->tt_ttisgmt = false;
+}
+
+static int_fast32_t
+detzcode(const char *const codep)
+{
+	register int_fast32_t	result;
+	register int		i;
+	int_fast32_t one = 1;
+	int_fast32_t halfmaxval = one << (32 - 2);
+	int_fast32_t maxval = halfmaxval - 1 + halfmaxval;
+	int_fast32_t minval = -1 - maxval;
+
+	result = codep[0] & 0x7f;
+	for (i = 1; i < 4; ++i)
+		result = (result << 8) | (codep[i] & 0xff);
+
+	if (codep[0] & 0x80) {
+	  /* Do two's-complement negation even on non-two's-complement machines.
+	     If the result would be minval - 1, return minval.  */
+	  result -= !TWOS_COMPLEMENT(int_fast32_t) && result != 0;
+	  result += minval;
+	}
+	return result;
+}
+
+static int_fast64_t
+detzcode64(const char *const codep)
+{
+	register uint_fast64_t result;
+	register int	i;
+	int_fast64_t one = 1;
+	int_fast64_t halfmaxval = one << (64 - 2);
+	int_fast64_t maxval = halfmaxval - 1 + halfmaxval;
+	int_fast64_t minval = -TWOS_COMPLEMENT(int_fast64_t) - maxval;
+
+	result = codep[0] & 0x7f;
+	for (i = 1; i < 8; ++i)
+		result = (result << 8) | (codep[i] & 0xff);
+
+	if (codep[0] & 0x80) {
+	  /* Do two's-complement negation even on non-two's-complement machines.
+	     If the result would be minval - 1, return minval.  */
+	  result -= !TWOS_COMPLEMENT(int_fast64_t) && result != 0;
+	  result += minval;
+	}
+	return result;
+}
+
+static void
+update_tzname_etc(struct state const *sp, struct ttinfo const *ttisp)
+{
+#if HAVE_TZNAME
+  tzname[ttisp->tt_isdst] = (char *) &sp->chars[ttisp->tt_abbrind];
+#endif
+#if USG_COMPAT
+  if (!ttisp->tt_isdst)
+    timezone = - ttisp->tt_gmtoff;
+#endif
+#ifdef ALTZONE
+  if (ttisp->tt_isdst)
+    altzone = - ttisp->tt_gmtoff;
+#endif
+}
+
+static void
+settzname(void)
+{
+	register struct state * const	sp = lclptr;
+	register int			i;
+
+#if HAVE_TZNAME
+	tzname[0] = tzname[1] = (char *) (sp ? wildabbr : gmt);
+#endif
+#if USG_COMPAT
+	daylight = 0;
+	timezone = 0;
+#endif
+#ifdef ALTZONE
+	altzone = 0;
+#endif /* defined ALTZONE */
+	if (sp == NULL) {
+		return;
+	}
+	/*
+	** And to get the latest zone names into tzname. . .
+	*/
+	for (i = 0; i < sp->typecnt; ++i) {
+		register const struct ttinfo * const	ttisp = &sp->ttis[i];
+		update_tzname_etc(sp, ttisp);
+	}
+	for (i = 0; i < sp->timecnt; ++i) {
+		register const struct ttinfo * const	ttisp =
+							&sp->ttis[
+								sp->types[i]];
+		update_tzname_etc(sp, ttisp);
+#if USG_COMPAT
+		if (ttisp->tt_isdst)
+			daylight = 1;
+#endif
+	}
+}
+
+static void
+scrub_abbrs(struct state *sp)
+{
+	int i;
+	/*
+	** First, replace bogus characters.
+	*/
+	for (i = 0; i < sp->charcnt; ++i)
+		if (strchr(TZ_ABBR_CHAR_SET, sp->chars[i]) == NULL)
+			sp->chars[i] = TZ_ABBR_ERR_CHAR;
+	/*
+	** Second, truncate long abbreviations.
+	*/
+	for (i = 0; i < sp->typecnt; ++i) {
+		register const struct ttinfo * const	ttisp = &sp->ttis[i];
+		register char *				cp = &sp->chars[ttisp->tt_abbrind];
+
+		if (strlen(cp) > TZ_ABBR_MAX_LEN &&
+			strcmp(cp, GRANDPARENTED) != 0)
+				*(cp + TZ_ABBR_MAX_LEN) = '\0';
+	}
+}
+
+static bool
+differ_by_repeat(const time_t t1, const time_t t0)
+{
+	if (TYPE_BIT(time_t) - TYPE_SIGNED(time_t) < SECSPERREPEAT_BITS)
+		return 0;
+	return t1 - t0 == SECSPERREPEAT;
+}
+
+/* Input buffer for data read from a compiled tz file.  */
+union input_buffer {
+  /* The first part of the buffer, interpreted as a header.  */
+  struct tzhead tzhead;
+
+  /* The entire buffer.  */
+  char buf[2 * sizeof(struct tzhead) + 2 * sizeof (struct state)
+	   + 4 * TZ_MAX_TIMES];
+};
+
+/* TZDIR with a trailing '/' rather than a trailing '\0'.  */
+static char const tzdirslash[sizeof TZDIR] = TZDIR "/";
+
+/* Local storage needed for 'tzloadbody'.  */
+union local_storage {
+  /* The results of analyzing the file's contents after it is opened.  */
+  struct file_analysis {
+    /* The input buffer.  */
+    union input_buffer u;
+
+    /* A temporary state used for parsing a TZ string in the file.  */
+    struct state st;
+  } u;
+
+  /* The file name to be opened.  */
+  char fullname[BIGGEST(sizeof (struct file_analysis),
+			sizeof tzdirslash + 1024)];
+};
+
+/* Load tz data from the file named NAME into *SP.  Read extended
+   format if DOEXTEND.  Use *LSP for temporary storage.  Return 0 on
+   success, an errno value on failure.  */
+static int
+tzloadbody(char const *name, struct state *sp, bool doextend,
+	   union local_storage *lsp)
+{
+	register int			i;
+	register int			fid;
+	register int			stored;
+	register ssize_t		nread;
+	register bool doaccess;
+	register union input_buffer *up = &lsp->u.u;
+	register int tzheadsize = sizeof (struct tzhead);
+
+	sp->goback = sp->goahead = false;
+
+	if (! name) {
+		name = TZDEFAULT;
+		if (! name)
+		  return EINVAL;
+	}
+
+	if (name[0] == ':')
+		++name;
+#ifdef SUPPRESS_TZDIR
+	/* Do not prepend TZDIR.  This is intended for specialized
+	   applications only, due to its security implications.  */
+	doaccess = true;
+#else
+	doaccess = name[0] == '/';
+#endif
+	if (!doaccess) {
+		size_t namelen = strlen(name);
+		if (sizeof lsp->fullname - sizeof tzdirslash <= namelen)
+		  return ENAMETOOLONG;
+
+		/* Create a string "TZDIR/NAME".  Using sprintf here
+		   would pull in stdio (and would fail if the
+		   resulting string length exceeded INT_MAX!).  */
+		memcpy(lsp->fullname, tzdirslash, sizeof tzdirslash);
+		strcpy(lsp->fullname + sizeof tzdirslash, name);
+
+		/* Set doaccess if '.' (as in "../") shows up in name.  */
+		if (strchr(name, '.'))
+			doaccess = true;
+		name = lsp->fullname;
+	}
+	if (doaccess && access(name, R_OK) != 0)
+	  return errno;
+	fid = open(name, OPEN_MODE);
+	if (fid < 0)
+	  return errno;
+
+	nread = read(fid, up->buf, sizeof up->buf);
+	if (nread < tzheadsize) {
+	  int err = nread < 0 ? errno : EINVAL;
+	  close(fid);
+	  return err;
+	}
+	if (close(fid) < 0)
+	  return errno;
+	for (stored = 4; stored <= 8; stored *= 2) {
+		int_fast32_t ttisstdcnt = detzcode(up->tzhead.tzh_ttisstdcnt);
+		int_fast32_t ttisgmtcnt = detzcode(up->tzhead.tzh_ttisgmtcnt);
+		int_fast64_t prevtr = 0;
+		int_fast32_t prevcorr = 0;
+		int_fast32_t leapcnt = detzcode(up->tzhead.tzh_leapcnt);
+		int_fast32_t timecnt = detzcode(up->tzhead.tzh_timecnt);
+		int_fast32_t typecnt = detzcode(up->tzhead.tzh_typecnt);
+		int_fast32_t charcnt = detzcode(up->tzhead.tzh_charcnt);
+		char const *p = up->buf + tzheadsize;
+		if (! (0 <= leapcnt && leapcnt < TZ_MAX_LEAPS
+		       && 0 < typecnt && typecnt < TZ_MAX_TYPES
+		       && 0 <= timecnt && timecnt < TZ_MAX_TIMES
+		       && 0 <= charcnt && charcnt < TZ_MAX_CHARS
+		       && (ttisstdcnt == typecnt || ttisstdcnt == 0)
+		       && (ttisgmtcnt == typecnt || ttisgmtcnt == 0)))
+		  return EINVAL;
+		if (nread
+		    < (tzheadsize		/* struct tzhead */
+		       + timecnt * stored	/* ats */
+		       + timecnt		/* types */
+		       + typecnt * 6		/* ttinfos */
+		       + charcnt		/* chars */
+		       + leapcnt * (stored + 4)	/* lsinfos */
+		       + ttisstdcnt		/* ttisstds */
+		       + ttisgmtcnt))		/* ttisgmts */
+		  return EINVAL;
+		sp->leapcnt = leapcnt;
+		sp->timecnt = timecnt;
+		sp->typecnt = typecnt;
+		sp->charcnt = charcnt;
+
+		/* Read transitions, discarding those out of time_t range.
+		   But pretend the last transition before TIME_T_MIN
+		   occurred at TIME_T_MIN.  */
+		timecnt = 0;
+		for (i = 0; i < sp->timecnt; ++i) {
+			int_fast64_t at
+			  = stored == 4 ? detzcode(p) : detzcode64(p);
+			sp->types[i] = at <= TIME_T_MAX;
+			if (sp->types[i]) {
+			  time_t attime
+			    = ((TYPE_SIGNED(time_t) ? at < TIME_T_MIN : at < 0)
+			       ? TIME_T_MIN : at);
+			  if (timecnt && attime <= sp->ats[timecnt - 1]) {
+			    if (attime < sp->ats[timecnt - 1])
+			      return EINVAL;
+			    sp->types[i - 1] = 0;
+			    timecnt--;
+			  }
+			  sp->ats[timecnt++] = attime;
+			}
+			p += stored;
+		}
+
+		timecnt = 0;
+		for (i = 0; i < sp->timecnt; ++i) {
+			unsigned char typ = *p++;
+			if (sp->typecnt <= typ)
+			  return EINVAL;
+			if (sp->types[i])
+				sp->types[timecnt++] = typ;
+		}
+		sp->timecnt = timecnt;
+		for (i = 0; i < sp->typecnt; ++i) {
+			register struct ttinfo *	ttisp;
+			unsigned char isdst, abbrind;
+
+			ttisp = &sp->ttis[i];
+			ttisp->tt_gmtoff = detzcode(p);
+			p += 4;
+			isdst = *p++;
+			if (! (isdst < 2))
+			  return EINVAL;
+			ttisp->tt_isdst = isdst;
+			abbrind = *p++;
+			if (! (abbrind < sp->charcnt))
+			  return EINVAL;
+			ttisp->tt_abbrind = abbrind;
+		}
+		for (i = 0; i < sp->charcnt; ++i)
+			sp->chars[i] = *p++;
+		sp->chars[i] = '\0';	/* ensure '\0' at end */
+
+		/* Read leap seconds, discarding those out of time_t range.  */
+		leapcnt = 0;
+		for (i = 0; i < sp->leapcnt; ++i) {
+		  int_fast64_t tr = stored == 4 ? detzcode(p) : detzcode64(p);
+		  int_fast32_t corr = detzcode(p + stored);
+		  p += stored + 4;
+		  /* Leap seconds cannot occur before the Epoch.  */
+		  if (tr < 0)
+		    return EINVAL;
+		  if (tr <= TIME_T_MAX) {
+		    /* Leap seconds cannot occur more than once per UTC month,
+		       and UTC months are at least 28 days long (minus 1
+		       second for a negative leap second).  Each leap second's
+		       correction must differ from the previous one's by 1
+		       second.  */
+		    if (tr - prevtr < 28 * SECSPERDAY - 1
+			|| (corr != prevcorr - 1 && corr != prevcorr + 1))
+		      return EINVAL;
+		    sp->lsis[leapcnt].ls_trans = prevtr = tr;
+		    sp->lsis[leapcnt].ls_corr = prevcorr = corr;
+		    leapcnt++;
+		  }
+		}
+		sp->leapcnt = leapcnt;
+
+		for (i = 0; i < sp->typecnt; ++i) {
+			register struct ttinfo *	ttisp;
+
+			ttisp = &sp->ttis[i];
+			if (ttisstdcnt == 0)
+				ttisp->tt_ttisstd = false;
+			else {
+				if (*p != true && *p != false)
+				  return EINVAL;
+				ttisp->tt_ttisstd = *p++;
+			}
+		}
+		for (i = 0; i < sp->typecnt; ++i) {
+			register struct ttinfo *	ttisp;
+
+			ttisp = &sp->ttis[i];
+			if (ttisgmtcnt == 0)
+				ttisp->tt_ttisgmt = false;
+			else {
+				if (*p != true && *p != false)
+						return EINVAL;
+				ttisp->tt_ttisgmt = *p++;
+			}
+		}
+		/*
+		** If this is an old file, we're done.
+		*/
+		if (up->tzhead.tzh_version[0] == '\0')
+			break;
+		nread -= p - up->buf;
+		memmove(up->buf, p, nread);
+	}
+	if (doextend && nread > 2 &&
+		up->buf[0] == '\n' && up->buf[nread - 1] == '\n' &&
+		sp->typecnt + 2 <= TZ_MAX_TYPES) {
+			struct state	*ts = &lsp->u.st;
+
+			up->buf[nread - 1] = '\0';
+			if (tzparse(&up->buf[1], ts, false)
+			    && ts->typecnt == 2) {
+
+			  /* Attempt to reuse existing abbreviations.
+			     Without this, America/Anchorage would be right on
+			     the edge after 2037 when TZ_MAX_CHARS is 50, as
+			     sp->charcnt equals 40 (for LMT AST AWT APT AHST
+			     AHDT YST AKDT AKST) and ts->charcnt equals 10
+			     (for AKST AKDT).  Reusing means sp->charcnt can
+			     stay 40 in this example.  */
+			  int gotabbr = 0;
+			  int charcnt = sp->charcnt;
+			  for (i = 0; i < 2; i++) {
+			    char *tsabbr = ts->chars + ts->ttis[i].tt_abbrind;
+			    int j;
+			    for (j = 0; j < charcnt; j++)
+			      if (strcmp(sp->chars + j, tsabbr) == 0) {
+				ts->ttis[i].tt_abbrind = j;
+				gotabbr++;
+				break;
+			      }
+			    if (! (j < charcnt)) {
+			      int tsabbrlen = strlen(tsabbr);
+			      if (j + tsabbrlen < TZ_MAX_CHARS) {
+				strcpy(sp->chars + j, tsabbr);
+				charcnt = j + tsabbrlen + 1;
+				ts->ttis[i].tt_abbrind = j;
+				gotabbr++;
+			      }
+			    }
+			  }
+			  if (gotabbr == 2) {
+			    sp->charcnt = charcnt;
+
+			    /* Ignore any trailing, no-op transitions generated
+			       by zic as they don't help here and can run afoul
+			       of bugs in zic 2016j or earlier.  */
+			    while (1 < sp->timecnt
+				   && (sp->types[sp->timecnt - 1]
+				       == sp->types[sp->timecnt - 2]))
+			      sp->timecnt--;
+
+			    for (i = 0; i < ts->timecnt; i++)
+			      if (sp->ats[sp->timecnt - 1] < ts->ats[i])
+				break;
+			    while (i < ts->timecnt
+				   && sp->timecnt < TZ_MAX_TIMES) {
+			      sp->ats[sp->timecnt] = ts->ats[i];
+			      sp->types[sp->timecnt] = (sp->typecnt
+							+ ts->types[i]);
+			      sp->timecnt++;
+			      i++;
+			    }
+			    sp->ttis[sp->typecnt++] = ts->ttis[0];
+			    sp->ttis[sp->typecnt++] = ts->ttis[1];
+			  }
+			}
+	}
+	if (sp->timecnt > 1) {
+		for (i = 1; i < sp->timecnt; ++i)
+			if (typesequiv(sp, sp->types[i], sp->types[0]) &&
+				differ_by_repeat(sp->ats[i], sp->ats[0])) {
+					sp->goback = true;
+					break;
+				}
+		for (i = sp->timecnt - 2; i >= 0; --i)
+			if (typesequiv(sp, sp->types[sp->timecnt - 1],
+				sp->types[i]) &&
+				differ_by_repeat(sp->ats[sp->timecnt - 1],
+				sp->ats[i])) {
+					sp->goahead = true;
+					break;
+		}
+	}
+	/*
+	** If type 0 is unused in transitions,
+	** it's the type to use for early times.
+	*/
+	for (i = 0; i < sp->timecnt; ++i)
+		if (sp->types[i] == 0)
+			break;
+	i = i < sp->timecnt ? -1 : 0;
+	/*
+	** Absent the above,
+	** if there are transition times
+	** and the first transition is to a daylight time
+	** find the standard type less than and closest to
+	** the type of the first transition.
+	*/
+	if (i < 0 && sp->timecnt > 0 && sp->ttis[sp->types[0]].tt_isdst) {
+		i = sp->types[0];
+		while (--i >= 0)
+			if (!sp->ttis[i].tt_isdst)
+				break;
+	}
+	/*
+	** If no result yet, find the first standard type.
+	** If there is none, punt to type zero.
+	*/
+	if (i < 0) {
+		i = 0;
+		while (sp->ttis[i].tt_isdst)
+			if (++i >= sp->typecnt) {
+				i = 0;
+				break;
+			}
+	}
+	sp->defaulttype = i;
+	return 0;
+}
+
+/* Load tz data from the file named NAME into *SP.  Read extended
+   format if DOEXTEND.  Return 0 on success, an errno value on failure.  */
+static int
+tzload(char const *name, struct state *sp, bool doextend)
+{
+#ifdef ALL_STATE
+  union local_storage *lsp = malloc(sizeof *lsp);
+  if (!lsp)
+    return errno;
+  else {
+    int err = tzloadbody(name, sp, doextend, lsp);
+    free(lsp);
+    return err;
+  }
+#else
+  union local_storage ls;
+  return tzloadbody(name, sp, doextend, &ls);
+#endif
+}
+
+static bool
+typesequiv(const struct state *sp, int a, int b)
+{
+	register bool result;
+
+	if (sp == NULL ||
+		a < 0 || a >= sp->typecnt ||
+		b < 0 || b >= sp->typecnt)
+			result = false;
+	else {
+		register const struct ttinfo *	ap = &sp->ttis[a];
+		register const struct ttinfo *	bp = &sp->ttis[b];
+		result = ap->tt_gmtoff == bp->tt_gmtoff &&
+			ap->tt_isdst == bp->tt_isdst &&
+			ap->tt_ttisstd == bp->tt_ttisstd &&
+			ap->tt_ttisgmt == bp->tt_ttisgmt &&
+			strcmp(&sp->chars[ap->tt_abbrind],
+			&sp->chars[bp->tt_abbrind]) == 0;
+	}
+	return result;
+}
+
+static const int	mon_lengths[2][MONSPERYEAR] = {
+	{ 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 },
+	{ 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }
+};
+
+static const int	year_lengths[2] = {
+	DAYSPERNYEAR, DAYSPERLYEAR
+};
+
+/*
+** Given a pointer into a time zone string, scan until a character that is not
+** a valid character in a zone name is found. Return a pointer to that
+** character.
+*/
+
+static const char *
+getzname(register const char *strp)
+{
+	register char	c;
+
+	while ((c = *strp) != '\0' && !is_digit(c) && c != ',' && c != '-' &&
+		c != '+')
+			++strp;
+	return strp;
+}
+
+/*
+** Given a pointer into an extended time zone string, scan until the ending
+** delimiter of the zone name is located. Return a pointer to the delimiter.
+**
+** As with getzname above, the legal character set is actually quite
+** restricted, with other characters producing undefined results.
+** We don't do any checking here; checking is done later in common-case code.
+*/
+
+static const char *
+getqzname(register const char *strp, const int delim)
+{
+	register int	c;
+
+	while ((c = *strp) != '\0' && c != delim)
+		++strp;
+	return strp;
+}
+
+/*
+** Given a pointer into a time zone string, extract a number from that string.
+** Check that the number is within a specified range; if it is not, return
+** NULL.
+** Otherwise, return a pointer to the first character not part of the number.
+*/
+
+static const char *
+getnum(register const char *strp, int *const nump, const int min, const int max)
+{
+	register char	c;
+	register int	num;
+
+	if (strp == NULL || !is_digit(c = *strp))
+		return NULL;
+	num = 0;
+	do {
+		num = num * 10 + (c - '0');
+		if (num > max)
+			return NULL;	/* illegal value */
+		c = *++strp;
+	} while (is_digit(c));
+	if (num < min)
+		return NULL;		/* illegal value */
+	*nump = num;
+	return strp;
+}
+
+/*
+** Given a pointer into a time zone string, extract a number of seconds,
+** in hh[:mm[:ss]] form, from the string.
+** If any error occurs, return NULL.
+** Otherwise, return a pointer to the first character not part of the number
+** of seconds.
+*/
+
+static const char *
+getsecs(register const char *strp, int_fast32_t *const secsp)
+{
+	int	num;
+
+	/*
+	** 'HOURSPERDAY * DAYSPERWEEK - 1' allows quasi-Posix rules like
+	** "M10.4.6/26", which does not conform to Posix,
+	** but which specifies the equivalent of
+	** "02:00 on the first Sunday on or after 23 Oct".
+	*/
+	strp = getnum(strp, &num, 0, HOURSPERDAY * DAYSPERWEEK - 1);
+	if (strp == NULL)
+		return NULL;
+	*secsp = num * (int_fast32_t) SECSPERHOUR;
+	if (*strp == ':') {
+		++strp;
+		strp = getnum(strp, &num, 0, MINSPERHOUR - 1);
+		if (strp == NULL)
+			return NULL;
+		*secsp += num * SECSPERMIN;
+		if (*strp == ':') {
+			++strp;
+			/* 'SECSPERMIN' allows for leap seconds.  */
+			strp = getnum(strp, &num, 0, SECSPERMIN);
+			if (strp == NULL)
+				return NULL;
+			*secsp += num;
+		}
+	}
+	return strp;
+}
+
+/*
+** Given a pointer into a time zone string, extract an offset, in
+** [+-]hh[:mm[:ss]] form, from the string.
+** If any error occurs, return NULL.
+** Otherwise, return a pointer to the first character not part of the time.
+*/
+
+static const char *
+getoffset(register const char *strp, int_fast32_t *const offsetp)
+{
+	register bool neg = false;
+
+	if (*strp == '-') {
+		neg = true;
+		++strp;
+	} else if (*strp == '+')
+		++strp;
+	strp = getsecs(strp, offsetp);
+	if (strp == NULL)
+		return NULL;		/* illegal time */
+	if (neg)
+		*offsetp = -*offsetp;
+	return strp;
+}
+
+/*
+** Given a pointer into a time zone string, extract a rule in the form
+** date[/time]. See POSIX section 8 for the format of "date" and "time".
+** If a valid rule is not found, return NULL.
+** Otherwise, return a pointer to the first character not part of the rule.
+*/
+
+static const char *
+getrule(const char *strp, register struct rule *const rulep)
+{
+	if (*strp == 'J') {
+		/*
+		** Julian day.
+		*/
+		rulep->r_type = JULIAN_DAY;
+		++strp;
+		strp = getnum(strp, &rulep->r_day, 1, DAYSPERNYEAR);
+	} else if (*strp == 'M') {
+		/*
+		** Month, week, day.
+		*/
+		rulep->r_type = MONTH_NTH_DAY_OF_WEEK;
+		++strp;
+		strp = getnum(strp, &rulep->r_mon, 1, MONSPERYEAR);
+		if (strp == NULL)
+			return NULL;
+		if (*strp++ != '.')
+			return NULL;
+		strp = getnum(strp, &rulep->r_week, 1, 5);
+		if (strp == NULL)
+			return NULL;
+		if (*strp++ != '.')
+			return NULL;
+		strp = getnum(strp, &rulep->r_day, 0, DAYSPERWEEK - 1);
+	} else if (is_digit(*strp)) {
+		/*
+		** Day of year.
+		*/
+		rulep->r_type = DAY_OF_YEAR;
+		strp = getnum(strp, &rulep->r_day, 0, DAYSPERLYEAR - 1);
+	} else	return NULL;		/* invalid format */
+	if (strp == NULL)
+		return NULL;
+	if (*strp == '/') {
+		/*
+		** Time specified.
+		*/
+		++strp;
+		strp = getoffset(strp, &rulep->r_time);
+	} else	rulep->r_time = 2 * SECSPERHOUR;	/* default = 2:00:00 */
+	return strp;
+}
+
+/*
+** Given a year, a rule, and the offset from UT at the time that rule takes
+** effect, calculate the year-relative time that rule takes effect.
+*/
+
+static int_fast32_t
+transtime(const int year, register const struct rule *const rulep,
+	  const int_fast32_t offset)
+{
+	register bool	leapyear;
+	register int_fast32_t value;
+	register int	i;
+	int		d, m1, yy0, yy1, yy2, dow;
+
+	INITIALIZE(value);
+	leapyear = isleap(year);
+	switch (rulep->r_type) {
+
+	case JULIAN_DAY:
+		/*
+		** Jn - Julian day, 1 == January 1, 60 == March 1 even in leap
+		** years.
+		** In non-leap years, or if the day number is 59 or less, just
+		** add SECSPERDAY times the day number-1 to the time of
+		** January 1, midnight, to get the day.
+		*/
+		value = (rulep->r_day - 1) * SECSPERDAY;
+		if (leapyear && rulep->r_day >= 60)
+			value += SECSPERDAY;
+		break;
+
+	case DAY_OF_YEAR:
+		/*
+		** n - day of year.
+		** Just add SECSPERDAY times the day number to the time of
+		** January 1, midnight, to get the day.
+		*/
+		value = rulep->r_day * SECSPERDAY;
+		break;
+
+	case MONTH_NTH_DAY_OF_WEEK:
+		/*
+		** Mm.n.d - nth "dth day" of month m.
+		*/
+
+		/*
+		** Use Zeller's Congruence to get day-of-week of first day of
+		** month.
+		*/
+		m1 = (rulep->r_mon + 9) % 12 + 1;
+		yy0 = (rulep->r_mon <= 2) ? (year - 1) : year;
+		yy1 = yy0 / 100;
+		yy2 = yy0 % 100;
+		dow = ((26 * m1 - 2) / 10 +
+			1 + yy2 + yy2 / 4 + yy1 / 4 - 2 * yy1) % 7;
+		if (dow < 0)
+			dow += DAYSPERWEEK;
+
+		/*
+		** "dow" is the day-of-week of the first day of the month. Get
+		** the day-of-month (zero-origin) of the first "dow" day of the
+		** month.
+		*/
+		d = rulep->r_day - dow;
+		if (d < 0)
+			d += DAYSPERWEEK;
+		for (i = 1; i < rulep->r_week; ++i) {
+			if (d + DAYSPERWEEK >=
+				mon_lengths[leapyear][rulep->r_mon - 1])
+					break;
+			d += DAYSPERWEEK;
+		}
+
+		/*
+		** "d" is the day-of-month (zero-origin) of the day we want.
+		*/
+		value = d * SECSPERDAY;
+		for (i = 0; i < rulep->r_mon - 1; ++i)
+			value += mon_lengths[leapyear][i] * SECSPERDAY;
+		break;
+	}
+
+	/*
+	** "value" is the year-relative time of 00:00:00 UT on the day in
+	** question. To get the year-relative time of the specified local
+	** time on that day, add the transition time and the current offset
+	** from UT.
+	*/
+	return value + rulep->r_time + offset;
+}
+
+/*
+** Given a POSIX section 8-style TZ string, fill in the rule tables as
+** appropriate.
+*/
+
+static bool
+tzparse(const char *name, struct state *sp, bool lastditch)
+{
+	const char *			stdname;
+	const char *			dstname;
+	size_t				stdlen;
+	size_t				dstlen;
+	size_t				charcnt;
+	int_fast32_t			stdoffset;
+	int_fast32_t			dstoffset;
+	register char *			cp;
+	register bool			load_ok;
+
+	stdname = name;
+	if (lastditch) {
+		stdlen = sizeof gmt - 1;
+		name += stdlen;
+		stdoffset = 0;
+	} else {
+		if (*name == '<') {
+			name++;
+			stdname = name;
+			name = getqzname(name, '>');
+			if (*name != '>')
+			  return false;
+			stdlen = name - stdname;
+			name++;
+		} else {
+			name = getzname(name);
+			stdlen = name - stdname;
+		}
+		if (!stdlen)
+		  return false;
+		name = getoffset(name, &stdoffset);
+		if (name == NULL)
+		  return false;
+	}
+	charcnt = stdlen + 1;
+	if (sizeof sp->chars < charcnt)
+	  return false;
+	load_ok = tzload(TZDEFRULES, sp, false) == 0;
+	if (!load_ok)
+		sp->leapcnt = 0;		/* so, we're off a little */
+	if (*name != '\0') {
+		if (*name == '<') {
+			dstname = ++name;
+			name = getqzname(name, '>');
+			if (*name != '>')
+			  return false;
+			dstlen = name - dstname;
+			name++;
+		} else {
+			dstname = name;
+			name = getzname(name);
+			dstlen = name - dstname; /* length of DST zone name */
+		}
+		if (!dstlen)
+		  return false;
+		charcnt += dstlen + 1;
+		if (sizeof sp->chars < charcnt)
+		  return false;
+		if (*name != '\0' && *name != ',' && *name != ';') {
+			name = getoffset(name, &dstoffset);
+			if (name == NULL)
+			  return false;
+		} else	dstoffset = stdoffset - SECSPERHOUR;
+		if (*name == '\0' && !load_ok)
+			name = TZDEFRULESTRING;
+		if (*name == ',' || *name == ';') {
+			struct rule	start;
+			struct rule	end;
+			register int	year;
+			register int	yearlim;
+			register int	timecnt;
+			time_t		janfirst;
+			int_fast32_t janoffset = 0;
+			int yearbeg;
+
+			++name;
+			if ((name = getrule(name, &start)) == NULL)
+			  return false;
+			if (*name++ != ',')
+			  return false;
+			if ((name = getrule(name, &end)) == NULL)
+			  return false;
+			if (*name != '\0')
+			  return false;
+			sp->typecnt = 2;	/* standard time and DST */
+			/*
+			** Two transitions per year, from EPOCH_YEAR forward.
+			*/
+			init_ttinfo(&sp->ttis[0], -dstoffset, true, stdlen + 1);
+			init_ttinfo(&sp->ttis[1], -stdoffset, false, 0);
+			sp->defaulttype = 0;
+			timecnt = 0;
+			janfirst = 0;
+			yearbeg = EPOCH_YEAR;
+
+			do {
+			  int_fast32_t yearsecs
+			    = year_lengths[isleap(yearbeg - 1)] * SECSPERDAY;
+			  yearbeg--;
+			  if (increment_overflow_time(&janfirst, -yearsecs)) {
+			    janoffset = -yearsecs;
+			    break;
+			  }
+			} while (EPOCH_YEAR - YEARSPERREPEAT / 2 < yearbeg);
+
+			yearlim = yearbeg + YEARSPERREPEAT + 1;
+			for (year = yearbeg; year < yearlim; year++) {
+				int_fast32_t
+				  starttime = transtime(year, &start, stdoffset),
+				  endtime = transtime(year, &end, dstoffset);
+				int_fast32_t
+				  yearsecs = (year_lengths[isleap(year)]
+					      * SECSPERDAY);
+				bool reversed = endtime < starttime;
+				if (reversed) {
+					int_fast32_t swap = starttime;
+					starttime = endtime;
+					endtime = swap;
+				}
+				if (reversed
+				    || (starttime < endtime
+					&& (endtime - starttime
+					    < (yearsecs
+					       + (stdoffset - dstoffset))))) {
+					if (TZ_MAX_TIMES - 2 < timecnt)
+						break;
+					sp->ats[timecnt] = janfirst;
+					if (! increment_overflow_time
+					    (&sp->ats[timecnt],
+					     janoffset + starttime))
+					  sp->types[timecnt++] = reversed;
+					else if (janoffset)
+					  sp->defaulttype = reversed;
+					sp->ats[timecnt] = janfirst;
+					if (! increment_overflow_time
+					    (&sp->ats[timecnt],
+					     janoffset + endtime)) {
+					  sp->types[timecnt++] = !reversed;
+					  yearlim = year + YEARSPERREPEAT + 1;
+					} else if (janoffset)
+					  sp->defaulttype = !reversed;
+				}
+				if (increment_overflow_time
+				    (&janfirst, janoffset + yearsecs))
+					break;
+				janoffset = 0;
+			}
+			sp->timecnt = timecnt;
+			if (! timecnt)
+				sp->typecnt = 1;	/* Perpetual DST.  */
+			else if (YEARSPERREPEAT < year - yearbeg)
+				sp->goback = sp->goahead = true;
+		} else {
+			register int_fast32_t	theirstdoffset;
+			register int_fast32_t	theirdstoffset;
+			register int_fast32_t	theiroffset;
+			register bool		isdst;
+			register int		i;
+			register int		j;
+
+			if (*name != '\0')
+			  return false;
+			/*
+			** Initial values of theirstdoffset and theirdstoffset.
+			*/
+			theirstdoffset = 0;
+			for (i = 0; i < sp->timecnt; ++i) {
+				j = sp->types[i];
+				if (!sp->ttis[j].tt_isdst) {
+					theirstdoffset =
+						-sp->ttis[j].tt_gmtoff;
+					break;
+				}
+			}
+			theirdstoffset = 0;
+			for (i = 0; i < sp->timecnt; ++i) {
+				j = sp->types[i];
+				if (sp->ttis[j].tt_isdst) {
+					theirdstoffset =
+						-sp->ttis[j].tt_gmtoff;
+					break;
+				}
+			}
+			/*
+			** Initially we're assumed to be in standard time.
+			*/
+			isdst = false;
+			theiroffset = theirstdoffset;
+			/*
+			** Now juggle transition times and types
+			** tracking offsets as you do.
+			*/
+			for (i = 0; i < sp->timecnt; ++i) {
+				j = sp->types[i];
+				sp->types[i] = sp->ttis[j].tt_isdst;
+				if (sp->ttis[j].tt_ttisgmt) {
+					/* No adjustment to transition time */
+				} else {
+					/*
+					** If daylight saving time is in
+					** effect, and the transition time was
+					** not specified as standard time, add
+					** the daylight saving time offset to
+					** the transition time; otherwise, add
+					** the standard time offset to the
+					** transition time.
+					*/
+					/*
+					** Transitions from DST to DDST
+					** will effectively disappear since
+					** POSIX provides for only one DST
+					** offset.
+					*/
+					if (isdst && !sp->ttis[j].tt_ttisstd) {
+						sp->ats[i] += dstoffset -
+							theirdstoffset;
+					} else {
+						sp->ats[i] += stdoffset -
+							theirstdoffset;
+					}
+				}
+				theiroffset = -sp->ttis[j].tt_gmtoff;
+				if (sp->ttis[j].tt_isdst)
+					theirdstoffset = theiroffset;
+				else	theirstdoffset = theiroffset;
+			}
+			/*
+			** Finally, fill in ttis.
+			*/
+			init_ttinfo(&sp->ttis[0], -stdoffset, false, 0);
+			init_ttinfo(&sp->ttis[1], -dstoffset, true, stdlen + 1);
+			sp->typecnt = 2;
+			sp->defaulttype = 0;
+		}
+	} else {
+		dstlen = 0;
+		sp->typecnt = 1;		/* only standard time */
+		sp->timecnt = 0;
+		init_ttinfo(&sp->ttis[0], -stdoffset, false, 0);
+		sp->defaulttype = 0;
+	}
+	sp->charcnt = charcnt;
+	cp = sp->chars;
+	memcpy(cp, stdname, stdlen);
+	cp += stdlen;
+	*cp++ = '\0';
+	if (dstlen != 0) {
+		memcpy(cp, dstname, dstlen);
+		*(cp + dstlen) = '\0';
+	}
+	return true;
+}
+
+static void
+gmtload(struct state *const sp)
+{
+	if (tzload(gmt, sp, true) != 0)
+		tzparse(gmt, sp, true);
+}
+
+/* Initialize *SP to a value appropriate for the TZ setting NAME.
+   Return 0 on success, an errno value on failure.  */
+static int
+zoneinit(struct state *sp, char const *name)
+{
+  if (name && ! name[0]) {
+    /*
+    ** User wants it fast rather than right.
+    */
+    sp->leapcnt = 0;		/* so, we're off a little */
+    sp->timecnt = 0;
+    sp->typecnt = 0;
+    sp->charcnt = 0;
+    sp->goback = sp->goahead = false;
+    init_ttinfo(&sp->ttis[0], 0, false, 0);
+    strcpy(sp->chars, gmt);
+    sp->defaulttype = 0;
+    return 0;
+  } else {
+    int err = tzload(name, sp, true);
+    if (err != 0 && name && name[0] != ':' && tzparse(name, sp, false))
+      err = 0;
+    if (err == 0)
+      scrub_abbrs(sp);
+    return err;
+  }
+}
+
+static void
+tzsetlcl(char const *name)
+{
+  struct state *sp = lclptr;
+  int lcl = name ? strlen(name) < sizeof lcl_TZname : -1;
+  if (lcl < 0
+      ? lcl_is_set < 0
+      : 0 < lcl_is_set && strcmp(lcl_TZname, name) == 0)
+    return;
+#ifdef ALL_STATE
+  if (! sp)
+    lclptr = sp = malloc(sizeof *lclptr);
+#endif /* defined ALL_STATE */
+  if (sp) {
+    if (zoneinit(sp, name) != 0)
+      zoneinit(sp, "");
+    if (0 < lcl)
+      strcpy(lcl_TZname, name);
+  }
+  settzname();
+  lcl_is_set = lcl;
+}
+
+#ifdef STD_INSPIRED
+void
+tzsetwall(void)
+{
+  if (lock() != 0)
+    return;
+  tzsetlcl(NULL);
+  unlock();
+}
+#endif
+
+static void
+tzset_unlocked(void)
+{
+  tzsetlcl(getenv("TZ"));
+}
+
+void
+tzset(void)
+{
+  if (lock() != 0)
+    return;
+  tzset_unlocked();
+  unlock();
+}
+
+static void
+gmtcheck(void)
+{
+  static bool gmt_is_set;
+  if (lock() != 0)
+    return;
+  if (! gmt_is_set) {
+#ifdef ALL_STATE
+    gmtptr = malloc(sizeof *gmtptr);
+#endif
+    if (gmtptr)
+      gmtload(gmtptr);
+    gmt_is_set = true;
+  }
+  unlock();
+}
+
+#if NETBSD_INSPIRED
+
+timezone_t
+tzalloc(char const *name)
+{
+  timezone_t sp = malloc(sizeof *sp);
+  if (sp) {
+    int err = zoneinit(sp, name);
+    if (err != 0) {
+      free(sp);
+      errno = err;
+      return NULL;
+    }
+  }
+  return sp;
+}
+
+void
+tzfree(timezone_t sp)
+{
+  free(sp);
+}
+
+/*
+** NetBSD 6.1.4 has ctime_rz, but omit it because POSIX says ctime and
+** ctime_r are obsolescent and have potential security problems that
+** ctime_rz would share.  Callers can instead use localtime_rz + strftime.
+**
+** NetBSD 6.1.4 has tzgetname, but omit it because it doesn't work
+** in zones with three or more time zone abbreviations.
+** Callers can instead use localtime_rz + strftime.
+*/
+
+#endif
+
+/*
+** The easy way to behave "as if no library function calls" localtime
+** is to not call it, so we drop its guts into "localsub", which can be
+** freely called. (And no, the PANS doesn't require the above behavior,
+** but it *is* desirable.)
+**
+** If successful and SETNAME is nonzero,
+** set the applicable parts of tzname, timezone and altzone;
+** however, it's OK to omit this step if the time zone is POSIX-compatible,
+** since in that case tzset should have already done this step correctly.
+** SETNAME's type is intfast32_t for compatibility with gmtsub,
+** but it is actually a boolean and its value should be 0 or 1.
+*/
+
+/*ARGSUSED*/
+static struct tm *
+localsub(struct state const *sp, time_t const *timep, int_fast32_t setname,
+	 struct tm *const tmp)
+{
+	register const struct ttinfo *	ttisp;
+	register int			i;
+	register struct tm *		result;
+	const time_t			t = *timep;
+
+	if (sp == NULL) {
+	  /* Don't bother to set tzname etc.; tzset has already done it.  */
+	  return gmtsub(gmtptr, timep, 0, tmp);
+	}
+	if ((sp->goback && t < sp->ats[0]) ||
+		(sp->goahead && t > sp->ats[sp->timecnt - 1])) {
+			time_t			newt = t;
+			register time_t		seconds;
+			register time_t		years;
+
+			if (t < sp->ats[0])
+				seconds = sp->ats[0] - t;
+			else	seconds = t - sp->ats[sp->timecnt - 1];
+			--seconds;
+			years = (seconds / SECSPERREPEAT + 1) * YEARSPERREPEAT;
+			seconds = years * AVGSECSPERYEAR;
+			if (t < sp->ats[0])
+				newt += seconds;
+			else	newt -= seconds;
+			if (newt < sp->ats[0] ||
+				newt > sp->ats[sp->timecnt - 1])
+					return NULL;	/* "cannot happen" */
+			result = localsub(sp, &newt, setname, tmp);
+			if (result) {
+				register int_fast64_t newy;
+
+				newy = result->tm_year;
+				if (t < sp->ats[0])
+					newy -= years;
+				else	newy += years;
+				if (! (INT_MIN <= newy && newy <= INT_MAX))
+					return NULL;
+				result->tm_year = newy;
+			}
+			return result;
+	}
+	if (sp->timecnt == 0 || t < sp->ats[0]) {
+		i = sp->defaulttype;
+	} else {
+		register int	lo = 1;
+		register int	hi = sp->timecnt;
+
+		while (lo < hi) {
+			register int	mid = (lo + hi) >> 1;
+
+			if (t < sp->ats[mid])
+				hi = mid;
+			else	lo = mid + 1;
+		}
+		i = (int) sp->types[lo - 1];
+	}
+	ttisp = &sp->ttis[i];
+	/*
+	** To get (wrong) behavior that's compatible with System V Release 2.0
+	** you'd replace the statement below with
+	**	t += ttisp->tt_gmtoff;
+	**	timesub(&t, 0L, sp, tmp);
+	*/
+	result = timesub(&t, ttisp->tt_gmtoff, sp, tmp);
+	if (result) {
+	  result->tm_isdst = ttisp->tt_isdst;
+#ifdef TM_ZONE
+	  result->TM_ZONE = (char *) &sp->chars[ttisp->tt_abbrind];
+#endif /* defined TM_ZONE */
+	  if (setname)
+	    update_tzname_etc(sp, ttisp);
+	}
+	return result;
+}
+
+#if NETBSD_INSPIRED
+
+struct tm *
+localtime_rz(struct state *sp, time_t const *timep, struct tm *tmp)
+{
+  return localsub(sp, timep, 0, tmp);
+}
+
+#endif
+
+static struct tm *
+localtime_tzset(time_t const *timep, struct tm *tmp, bool setname)
+{
+  int err = lock();
+  if (err) {
+    errno = err;
+    return NULL;
+  }
+  if (setname || !lcl_is_set)
+    tzset_unlocked();
+  tmp = localsub(lclptr, timep, setname, tmp);
+  unlock();
+  return tmp;
+}
+
+struct tm *
+localtime(const time_t *timep)
+{
+  return localtime_tzset(timep, &tm, true);
+}
+
+struct tm *
+localtime_r(const time_t *timep, struct tm *tmp)
+{
+  return localtime_tzset(timep, tmp, false);
+}
+
+/*
+** gmtsub is to gmtime as localsub is to localtime.
+*/
+
+static struct tm *
+gmtsub(struct state const *sp, time_t const *timep, int_fast32_t offset,
+       struct tm *tmp)
+{
+	register struct tm *	result;
+
+	result = timesub(timep, offset, gmtptr, tmp);
+#ifdef TM_ZONE
+	/*
+	** Could get fancy here and deliver something such as
+	** "+xx" or "-xx" if offset is non-zero,
+	** but this is no time for a treasure hunt.
+	*/
+	tmp->TM_ZONE = ((char *)
+			(offset ? wildabbr : gmtptr ? gmtptr->chars : gmt));
+#endif /* defined TM_ZONE */
+	return result;
+}
+
+/*
+* Re-entrant version of gmtime.
+*/
+
+struct tm *
+gmtime_r(const time_t *timep, struct tm *tmp)
+{
+  gmtcheck();
+  return gmtsub(gmtptr, timep, 0, tmp);
+}
+
+struct tm *
+gmtime(const time_t *timep)
+{
+  return gmtime_r(timep, &tm);
+}
+
+#ifdef STD_INSPIRED
+
+struct tm *
+offtime(const time_t *timep, long offset)
+{
+  gmtcheck();
+  return gmtsub(gmtptr, timep, offset, &tm);
+}
+
+#endif /* defined STD_INSPIRED */
+
+/*
+** Return the number of leap years through the end of the given year
+** where, to make the math easy, the answer for year zero is defined as zero.
+*/
+
+static int
+leaps_thru_end_of_nonneg(int y)
+{
+  return y / 4 - y / 100 + y / 400;
+}
+
+static int
+leaps_thru_end_of(register const int y)
+{
+  return (y < 0
+	  ? -1 - leaps_thru_end_of_nonneg(-1 - y)
+	  : leaps_thru_end_of_nonneg(y));
+}
+
+static struct tm *
+timesub(const time_t *timep, int_fast32_t offset,
+	const struct state *sp, struct tm *tmp)
+{
+	register const struct lsinfo *	lp;
+	register time_t			tdays;
+	register int			idays;	/* unsigned would be so 2003 */
+	register int_fast64_t		rem;
+	int				y;
+	register const int *		ip;
+	register int_fast64_t		corr;
+	register bool			hit;
+	register int			i;
+
+	corr = 0;
+	hit = false;
+	i = (sp == NULL) ? 0 : sp->leapcnt;
+	while (--i >= 0) {
+		lp = &sp->lsis[i];
+		if (*timep >= lp->ls_trans) {
+			corr = lp->ls_corr;
+			hit = (*timep == lp->ls_trans
+			       && (i == 0 ? 0 : lp[-1].ls_corr) < corr);
+			break;
+		}
+	}
+	y = EPOCH_YEAR;
+	tdays = *timep / SECSPERDAY;
+	rem = *timep % SECSPERDAY;
+	while (tdays < 0 || tdays >= year_lengths[isleap(y)]) {
+		int		newy;
+		register time_t	tdelta;
+		register int	idelta;
+		register int	leapdays;
+
+		tdelta = tdays / DAYSPERLYEAR;
+		if (! ((! TYPE_SIGNED(time_t) || INT_MIN <= tdelta)
+		       && tdelta <= INT_MAX))
+		  goto out_of_range;
+		idelta = tdelta;
+		if (idelta == 0)
+			idelta = (tdays < 0) ? -1 : 1;
+		newy = y;
+		if (increment_overflow(&newy, idelta))
+		  goto out_of_range;
+		leapdays = leaps_thru_end_of(newy - 1) -
+			leaps_thru_end_of(y - 1);
+		tdays -= ((time_t) newy - y) * DAYSPERNYEAR;
+		tdays -= leapdays;
+		y = newy;
+	}
+	/*
+	** Given the range, we can now fearlessly cast...
+	*/
+	idays = tdays;
+	rem += offset - corr;
+	while (rem < 0) {
+		rem += SECSPERDAY;
+		--idays;
+	}
+	while (rem >= SECSPERDAY) {
+		rem -= SECSPERDAY;
+		++idays;
+	}
+	while (idays < 0) {
+		if (increment_overflow(&y, -1))
+		  goto out_of_range;
+		idays += year_lengths[isleap(y)];
+	}
+	while (idays >= year_lengths[isleap(y)]) {
+		idays -= year_lengths[isleap(y)];
+		if (increment_overflow(&y, 1))
+		  goto out_of_range;
+	}
+	tmp->tm_year = y;
+	if (increment_overflow(&tmp->tm_year, -TM_YEAR_BASE))
+	  goto out_of_range;
+	tmp->tm_yday = idays;
+	/*
+	** The "extra" mods below avoid overflow problems.
+	*/
+	tmp->tm_wday = EPOCH_WDAY +
+		((y - EPOCH_YEAR) % DAYSPERWEEK) *
+		(DAYSPERNYEAR % DAYSPERWEEK) +
+		leaps_thru_end_of(y - 1) -
+		leaps_thru_end_of(EPOCH_YEAR - 1) +
+		idays;
+	tmp->tm_wday %= DAYSPERWEEK;
+	if (tmp->tm_wday < 0)
+		tmp->tm_wday += DAYSPERWEEK;
+	tmp->tm_hour = (int) (rem / SECSPERHOUR);
+	rem %= SECSPERHOUR;
+	tmp->tm_min = (int) (rem / SECSPERMIN);
+	/*
+	** A positive leap second requires a special
+	** representation. This uses "... ??:59:60" et seq.
+	*/
+	tmp->tm_sec = (int) (rem % SECSPERMIN) + hit;
+	ip = mon_lengths[isleap(y)];
+	for (tmp->tm_mon = 0; idays >= ip[tmp->tm_mon]; ++(tmp->tm_mon))
+		idays -= ip[tmp->tm_mon];
+	tmp->tm_mday = (int) (idays + 1);
+	tmp->tm_isdst = 0;
+#ifdef TM_GMTOFF
+	tmp->TM_GMTOFF = offset;
+#endif /* defined TM_GMTOFF */
+	return tmp;
+
+ out_of_range:
+	errno = EOVERFLOW;
+	return NULL;
+}
+
+char *
+ctime(const time_t *timep)
+{
+/*
+** Section 4.12.3.2 of X3.159-1989 requires that
+**	The ctime function converts the calendar time pointed to by timer
+**	to local time in the form of a string. It is equivalent to
+**		asctime(localtime(timer))
+*/
+  struct tm *tmp = localtime(timep);
+  return tmp ? asctime(tmp) : NULL;
+}
+
+char *
+ctime_r(const time_t *timep, char *buf)
+{
+  struct tm mytm;
+  struct tm *tmp = localtime_r(timep, &mytm);
+  return tmp ? asctime_r(tmp, buf) : NULL;
+}
+
+/*
+** Adapted from code provided by Robert Elz, who writes:
+**	The "best" way to do mktime I think is based on an idea of Bob
+**	Kridle's (so its said...) from a long time ago.
+**	It does a binary search of the time_t space. Since time_t's are
+**	just 32 bits, its a max of 32 iterations (even at 64 bits it
+**	would still be very reasonable).
+*/
+
+#ifndef WRONG
+#define WRONG	(-1)
+#endif /* !defined WRONG */
+
+/*
+** Normalize logic courtesy Paul Eggert.
+*/
+
+static bool
+increment_overflow(int *ip, int j)
+{
+	register int const	i = *ip;
+
+	/*
+	** If i >= 0 there can only be overflow if i + j > INT_MAX
+	** or if j > INT_MAX - i; given i >= 0, INT_MAX - i cannot overflow.
+	** If i < 0 there can only be overflow if i + j < INT_MIN
+	** or if j < INT_MIN - i; given i < 0, INT_MIN - i cannot overflow.
+	*/
+	if ((i >= 0) ? (j > INT_MAX - i) : (j < INT_MIN - i))
+		return true;
+	*ip += j;
+	return false;
+}
+
+static bool
+increment_overflow32(int_fast32_t *const lp, int const m)
+{
+	register int_fast32_t const	l = *lp;
+
+	if ((l >= 0) ? (m > INT_FAST32_MAX - l) : (m < INT_FAST32_MIN - l))
+		return true;
+	*lp += m;
+	return false;
+}
+
+static bool
+increment_overflow_time(time_t *tp, int_fast32_t j)
+{
+	/*
+	** This is like
+	** 'if (! (TIME_T_MIN <= *tp + j && *tp + j <= TIME_T_MAX)) ...',
+	** except that it does the right thing even if *tp + j would overflow.
+	*/
+	if (! (j < 0
+	       ? (TYPE_SIGNED(time_t) ? TIME_T_MIN - j <= *tp : -1 - j < *tp)
+	       : *tp <= TIME_T_MAX - j))
+		return true;
+	*tp += j;
+	return false;
+}
+
+static bool
+normalize_overflow(int *const tensptr, int *const unitsptr, const int base)
+{
+	register int	tensdelta;
+
+	tensdelta = (*unitsptr >= 0) ?
+		(*unitsptr / base) :
+		(-1 - (-1 - *unitsptr) / base);
+	*unitsptr -= tensdelta * base;
+	return increment_overflow(tensptr, tensdelta);
+}
+
+static bool
+normalize_overflow32(int_fast32_t *tensptr, int *unitsptr, int base)
+{
+	register int	tensdelta;
+
+	tensdelta = (*unitsptr >= 0) ?
+		(*unitsptr / base) :
+		(-1 - (-1 - *unitsptr) / base);
+	*unitsptr -= tensdelta * base;
+	return increment_overflow32(tensptr, tensdelta);
+}
+
+static int
+tmcomp(register const struct tm *const atmp,
+       register const struct tm *const btmp)
+{
+	register int	result;
+
+	if (atmp->tm_year != btmp->tm_year)
+		return atmp->tm_year < btmp->tm_year ? -1 : 1;
+	if ((result = (atmp->tm_mon - btmp->tm_mon)) == 0 &&
+		(result = (atmp->tm_mday - btmp->tm_mday)) == 0 &&
+		(result = (atmp->tm_hour - btmp->tm_hour)) == 0 &&
+		(result = (atmp->tm_min - btmp->tm_min)) == 0)
+			result = atmp->tm_sec - btmp->tm_sec;
+	return result;
+}
+
+static time_t
+time2sub(struct tm *const tmp,
+	 struct tm *(*funcp)(struct state const *, time_t const *,
+			     int_fast32_t, struct tm *),
+	 struct state const *sp,
+	 const int_fast32_t offset,
+	 bool *okayp,
+	 bool do_norm_secs)
+{
+	register int			dir;
+	register int			i, j;
+	register int			saved_seconds;
+	register int_fast32_t		li;
+	register time_t			lo;
+	register time_t			hi;
+	int_fast32_t			y;
+	time_t				newt;
+	time_t				t;
+	struct tm			yourtm, mytm;
+
+	*okayp = false;
+	yourtm = *tmp;
+	if (do_norm_secs) {
+		if (normalize_overflow(&yourtm.tm_min, &yourtm.tm_sec,
+			SECSPERMIN))
+				return WRONG;
+	}
+	if (normalize_overflow(&yourtm.tm_hour, &yourtm.tm_min, MINSPERHOUR))
+		return WRONG;
+	if (normalize_overflow(&yourtm.tm_mday, &yourtm.tm_hour, HOURSPERDAY))
+		return WRONG;
+	y = yourtm.tm_year;
+	if (normalize_overflow32(&y, &yourtm.tm_mon, MONSPERYEAR))
+		return WRONG;
+	/*
+	** Turn y into an actual year number for now.
+	** It is converted back to an offset from TM_YEAR_BASE later.
+	*/
+	if (increment_overflow32(&y, TM_YEAR_BASE))
+		return WRONG;
+	while (yourtm.tm_mday <= 0) {
+		if (increment_overflow32(&y, -1))
+			return WRONG;
+		li = y + (1 < yourtm.tm_mon);
+		yourtm.tm_mday += year_lengths[isleap(li)];
+	}
+	while (yourtm.tm_mday > DAYSPERLYEAR) {
+		li = y + (1 < yourtm.tm_mon);
+		yourtm.tm_mday -= year_lengths[isleap(li)];
+		if (increment_overflow32(&y, 1))
+			return WRONG;
+	}
+	for ( ; ; ) {
+		i = mon_lengths[isleap(y)][yourtm.tm_mon];
+		if (yourtm.tm_mday <= i)
+			break;
+		yourtm.tm_mday -= i;
+		if (++yourtm.tm_mon >= MONSPERYEAR) {
+			yourtm.tm_mon = 0;
+			if (increment_overflow32(&y, 1))
+				return WRONG;
+		}
+	}
+	if (increment_overflow32(&y, -TM_YEAR_BASE))
+		return WRONG;
+	if (! (INT_MIN <= y && y <= INT_MAX))
+		return WRONG;
+	yourtm.tm_year = y;
+	if (yourtm.tm_sec >= 0 && yourtm.tm_sec < SECSPERMIN)
+		saved_seconds = 0;
+	else if (y + TM_YEAR_BASE < EPOCH_YEAR) {
+		/*
+		** We can't set tm_sec to 0, because that might push the
+		** time below the minimum representable time.
+		** Set tm_sec to 59 instead.
+		** This assumes that the minimum representable time is
+		** not in the same minute that a leap second was deleted from,
+		** which is a safer assumption than using 58 would be.
+		*/
+		if (increment_overflow(&yourtm.tm_sec, 1 - SECSPERMIN))
+			return WRONG;
+		saved_seconds = yourtm.tm_sec;
+		yourtm.tm_sec = SECSPERMIN - 1;
+	} else {
+		saved_seconds = yourtm.tm_sec;
+		yourtm.tm_sec = 0;
+	}
+	/*
+	** Do a binary search (this works whatever time_t's type is).
+	*/
+	lo = TIME_T_MIN;
+	hi = TIME_T_MAX;
+	for ( ; ; ) {
+		t = lo / 2 + hi / 2;
+		if (t < lo)
+			t = lo;
+		else if (t > hi)
+			t = hi;
+		if (! funcp(sp, &t, offset, &mytm)) {
+			/*
+			** Assume that t is too extreme to be represented in
+			** a struct tm; arrange things so that it is less
+			** extreme on the next pass.
+			*/
+			dir = (t > 0) ? 1 : -1;
+		} else	dir = tmcomp(&mytm, &yourtm);
+		if (dir != 0) {
+			if (t == lo) {
+				if (t == TIME_T_MAX)
+					return WRONG;
+				++t;
+				++lo;
+			} else if (t == hi) {
+				if (t == TIME_T_MIN)
+					return WRONG;
+				--t;
+				--hi;
+			}
+			if (lo > hi)
+				return WRONG;
+			if (dir > 0)
+				hi = t;
+			else	lo = t;
+			continue;
+		}
+#if defined TM_GMTOFF && ! UNINIT_TRAP
+		if (mytm.TM_GMTOFF != yourtm.TM_GMTOFF
+		    && (yourtm.TM_GMTOFF < 0
+			? (-SECSPERDAY <= yourtm.TM_GMTOFF
+			   && (mytm.TM_GMTOFF <=
+			       (SMALLEST (INT_FAST32_MAX, LONG_MAX)
+				+ yourtm.TM_GMTOFF)))
+			: (yourtm.TM_GMTOFF <= SECSPERDAY
+			   && ((BIGGEST (INT_FAST32_MIN, LONG_MIN)
+				+ yourtm.TM_GMTOFF)
+			       <= mytm.TM_GMTOFF)))) {
+		  /* MYTM matches YOURTM except with the wrong UT offset.
+		     YOURTM.TM_GMTOFF is plausible, so try it instead.
+		     It's OK if YOURTM.TM_GMTOFF contains uninitialized data,
+		     since the guess gets checked.  */
+		  time_t altt = t;
+		  int_fast32_t diff = mytm.TM_GMTOFF - yourtm.TM_GMTOFF;
+		  if (!increment_overflow_time(&altt, diff)) {
+		    struct tm alttm;
+		    if (funcp(sp, &altt, offset, &alttm)
+			&& alttm.tm_isdst == mytm.tm_isdst
+			&& alttm.TM_GMTOFF == yourtm.TM_GMTOFF
+			&& tmcomp(&alttm, &yourtm) == 0) {
+		      t = altt;
+		      mytm = alttm;
+		    }
+		  }
+		}
+#endif
+		if (yourtm.tm_isdst < 0 || mytm.tm_isdst == yourtm.tm_isdst)
+			break;
+		/*
+		** Right time, wrong type.
+		** Hunt for right time, right type.
+		** It's okay to guess wrong since the guess
+		** gets checked.
+		*/
+		if (sp == NULL)
+			return WRONG;
+		for (i = sp->typecnt - 1; i >= 0; --i) {
+			if (sp->ttis[i].tt_isdst != yourtm.tm_isdst)
+				continue;
+			for (j = sp->typecnt - 1; j >= 0; --j) {
+				if (sp->ttis[j].tt_isdst == yourtm.tm_isdst)
+					continue;
+				newt = t + sp->ttis[j].tt_gmtoff -
+					sp->ttis[i].tt_gmtoff;
+				if (! funcp(sp, &newt, offset, &mytm))
+					continue;
+				if (tmcomp(&mytm, &yourtm) != 0)
+					continue;
+				if (mytm.tm_isdst != yourtm.tm_isdst)
+					continue;
+				/*
+				** We have a match.
+				*/
+				t = newt;
+				goto label;
+			}
+		}
+		return WRONG;
+	}
+label:
+	newt = t + saved_seconds;
+	if ((newt < t) != (saved_seconds < 0))
+		return WRONG;
+	t = newt;
+	if (funcp(sp, &t, offset, tmp))
+		*okayp = true;
+	return t;
+}
+
+static time_t
+time2(struct tm * const	tmp,
+      struct tm *(*funcp)(struct state const *, time_t const *,
+			  int_fast32_t, struct tm *),
+      struct state const *sp,
+      const int_fast32_t offset,
+      bool *okayp)
+{
+	time_t	t;
+
+	/*
+	** First try without normalization of seconds
+	** (in case tm_sec contains a value associated with a leap second).
+	** If that fails, try with normalization of seconds.
+	*/
+	t = time2sub(tmp, funcp, sp, offset, okayp, false);
+	return *okayp ? t : time2sub(tmp, funcp, sp, offset, okayp, true);
+}
+
+static time_t
+time1(struct tm *const tmp,
+      struct tm *(*funcp) (struct state const *, time_t const *,
+			   int_fast32_t, struct tm *),
+      struct state const *sp,
+      const int_fast32_t offset)
+{
+	register time_t			t;
+	register int			samei, otheri;
+	register int			sameind, otherind;
+	register int			i;
+	register int			nseen;
+	char				seen[TZ_MAX_TYPES];
+	unsigned char			types[TZ_MAX_TYPES];
+	bool				okay;
+
+	if (tmp == NULL) {
+		errno = EINVAL;
+		return WRONG;
+	}
+	if (tmp->tm_isdst > 1)
+		tmp->tm_isdst = 1;
+	t = time2(tmp, funcp, sp, offset, &okay);
+	if (okay)
+		return t;
+	if (tmp->tm_isdst < 0)
+#ifdef PCTS
+		/*
+		** POSIX Conformance Test Suite code courtesy Grant Sullivan.
+		*/
+		tmp->tm_isdst = 0;	/* reset to std and try again */
+#else
+		return t;
+#endif /* !defined PCTS */
+	/*
+	** We're supposed to assume that somebody took a time of one type
+	** and did some math on it that yielded a "struct tm" that's bad.
+	** We try to divine the type they started from and adjust to the
+	** type they need.
+	*/
+	if (sp == NULL)
+		return WRONG;
+	for (i = 0; i < sp->typecnt; ++i)
+		seen[i] = false;
+	nseen = 0;
+	for (i = sp->timecnt - 1; i >= 0; --i)
+		if (!seen[sp->types[i]]) {
+			seen[sp->types[i]] = true;
+			types[nseen++] = sp->types[i];
+		}
+	for (sameind = 0; sameind < nseen; ++sameind) {
+		samei = types[sameind];
+		if (sp->ttis[samei].tt_isdst != tmp->tm_isdst)
+			continue;
+		for (otherind = 0; otherind < nseen; ++otherind) {
+			otheri = types[otherind];
+			if (sp->ttis[otheri].tt_isdst == tmp->tm_isdst)
+				continue;
+			tmp->tm_sec += sp->ttis[otheri].tt_gmtoff -
+					sp->ttis[samei].tt_gmtoff;
+			tmp->tm_isdst = !tmp->tm_isdst;
+			t = time2(tmp, funcp, sp, offset, &okay);
+			if (okay)
+				return t;
+			tmp->tm_sec -= sp->ttis[otheri].tt_gmtoff -
+					sp->ttis[samei].tt_gmtoff;
+			tmp->tm_isdst = !tmp->tm_isdst;
+		}
+	}
+	return WRONG;
+}
+
+static time_t
+mktime_tzname(struct state *sp, struct tm *tmp, bool setname)
+{
+  if (sp)
+    return time1(tmp, localsub, sp, setname);
+  else {
+    gmtcheck();
+    return time1(tmp, gmtsub, gmtptr, 0);
+  }
+}
+
+#if NETBSD_INSPIRED
+
+time_t
+mktime_z(struct state *sp, struct tm *tmp)
+{
+  return mktime_tzname(sp, tmp, false);
+}
+
+#endif
+
+time_t
+mktime(struct tm *tmp)
+{
+  time_t t;
+  int err = lock();
+  if (err) {
+    errno = err;
+    return -1;
+  }
+  tzset_unlocked();
+  t = mktime_tzname(lclptr, tmp, true);
+  unlock();
+  return t;
+}
+
+#ifdef STD_INSPIRED
+
+time_t
+timelocal(struct tm *tmp)
+{
+	if (tmp != NULL)
+		tmp->tm_isdst = -1;	/* in case it wasn't initialized */
+	return mktime(tmp);
+}
+
+time_t
+timegm(struct tm *tmp)
+{
+  return timeoff(tmp, 0);
+}
+
+time_t
+timeoff(struct tm *tmp, long offset)
+{
+  if (tmp)
+    tmp->tm_isdst = 0;
+  gmtcheck();
+  return time1(tmp, gmtsub, gmtptr, offset);
+}
+
+#endif /* defined STD_INSPIRED */
+
+/*
+** XXX--is the below the right way to conditionalize??
+*/
+
+#ifdef STD_INSPIRED
+
+/*
+** IEEE Std 1003.1 (POSIX) says that 536457599
+** shall correspond to "Wed Dec 31 23:59:59 UTC 1986", which
+** is not the case if we are accounting for leap seconds.
+** So, we provide the following conversion routines for use
+** when exchanging timestamps with POSIX conforming systems.
+*/
+
+static int_fast64_t
+leapcorr(struct state const *sp, time_t t)
+{
+	register struct lsinfo const *	lp;
+	register int			i;
+
+	i = sp->leapcnt;
+	while (--i >= 0) {
+		lp = &sp->lsis[i];
+		if (t >= lp->ls_trans)
+			return lp->ls_corr;
+	}
+	return 0;
+}
+
+NETBSD_INSPIRED_EXTERN time_t
+time2posix_z(struct state *sp, time_t t)
+{
+  return t - leapcorr(sp, t);
+}
+
+time_t
+time2posix(time_t t)
+{
+  int err = lock();
+  if (err) {
+    errno = err;
+    return -1;
+  }
+  if (!lcl_is_set)
+    tzset_unlocked();
+  if (lclptr)
+    t = time2posix_z(lclptr, t);
+  unlock();
+  return t;
+}
+
+NETBSD_INSPIRED_EXTERN time_t
+posix2time_z(struct state *sp, time_t t)
+{
+	time_t	x;
+	time_t	y;
+	/*
+	** For a positive leap second hit, the result
+	** is not unique. For a negative leap second
+	** hit, the corresponding time doesn't exist,
+	** so we return an adjacent second.
+	*/
+	x = t + leapcorr(sp, t);
+	y = x - leapcorr(sp, x);
+	if (y < t) {
+		do {
+			x++;
+			y = x - leapcorr(sp, x);
+		} while (y < t);
+		x -= y != t;
+	} else if (y > t) {
+		do {
+			--x;
+			y = x - leapcorr(sp, x);
+		} while (y > t);
+		x += y != t;
+	}
+	return x;
+}
+
+time_t
+posix2time(time_t t)
+{
+  int err = lock();
+  if (err) {
+    errno = err;
+    return -1;
+  }
+  if (!lcl_is_set)
+    tzset_unlocked();
+  if (lclptr)
+    t = posix2time_z(lclptr, t);
+  unlock();
+  return t;
+}
+
+#endif /* defined STD_INSPIRED */
+
+#if TZ_TIME_T
+
+# if !USG_COMPAT
+#  define daylight 0
+#  define timezone 0
+# endif
+# ifndef ALTZONE
+#  define altzone 0
+# endif
+
+/* Convert from the underlying system's time_t to the ersatz time_tz,
+   which is called 'time_t' in this file.  Typically, this merely
+   converts the time's integer width.  On some platforms, the system
+   time is local time not UT, or uses some epoch other than the POSIX
+   epoch.
+
+   Although this code appears to define a function named 'time' that
+   returns time_t, the macros in private.h cause this code to actually
+   define a function named 'tz_time' that returns tz_time_t.  The call
+   to sys_time invokes the underlying system's 'time' function.  */
+
+time_t
+time(time_t *p)
+{
+  time_t r = sys_time(0);
+  if (r != (time_t) -1) {
+    int_fast32_t offset = EPOCH_LOCAL ? (daylight ? timezone : altzone) : 0;
+    if (increment_overflow32(&offset, -EPOCH_OFFSET)
+	|| increment_overflow_time (&r, offset)) {
+      errno = EOVERFLOW;
+      r = -1;
+    }
+  }
+  if (p)
+    *p = r;
+  return r;
+}
+
+#endif
diff --git a/newctime.3 b/newctime.3
new file mode 100644
index 000000000000..d4645adee62f
--- /dev/null
+++ b/newctime.3
@@ -0,0 +1,317 @@
+.TH NEWCTIME 3
+.SH NAME
+asctime, ctime, difftime, gmtime, localtime, mktime \- convert date and time
+.SH SYNOPSIS
+.nf
+.ie \n(.g .ds - \f(CW-\fP
+.el ds - \-
+.B #include <time.h>
+.PP
+.BR "extern char *tzname[];" " /\(** (optional) \(**/"
+.PP
+.B char *ctime(time_t const *clock);
+.PP
+.B char *ctime_r(time_t const *clock, char *buf);
+.PP
+.B double difftime(time_t time1, time_t time0);
+.PP
+.B char *asctime(struct tm const *tm);
+.PP
+.B "char *asctime_r(struct tm const *restrict tm,"
+.B "    char *restrict result);"
+.PP
+.B struct tm *localtime(time_t const *clock);
+.PP
+.B "struct tm *localtime_r(time_t const *restrict clock,"
+.B "    struct tm *restrict result);"
+.PP
+.B "struct tm *localtime_rz(timezone_t restrict zone,"
+.B "    time_t const *restrict clock,"
+.B "    struct tm *restrict result);"
+.PP
+.B struct tm *gmtime(time_t const *clock);
+.PP
+.B "struct tm *gmtime_r(time_t const *restrict clock,"
+.B "    struct tm *restrict result);"
+.PP
+.B time_t mktime(struct tm *tm);
+.PP
+.B "time_t mktime_z(timezone_t restrict zone,"
+.B "    struct tm *restrict tm);"
+.PP
+.B cc ... \*-ltz
+.fi
+.SH DESCRIPTION
+.ie '\(en'' .ds en \-
+.el .ds en \(en
+.ie '\(lq'' .ds lq \&"\"
+.el .ds lq \(lq\"
+.ie '\(rq'' .ds rq \&"\"
+.el .ds rq \(rq\"
+.de q
+\\$3\*(lq\\$1\*(rq\\$2
+..
+.I Ctime
+converts a long integer, pointed to by
+.IR clock ,
+and returns a pointer to a
+string of the form
+.br
+.ce
+.eo
+Thu Nov 24 18:22:48 1986\n\0
+.br
+.ec
+Years requiring fewer than four characters are padded with leading zeroes.
+For years longer than four characters, the string is of the form
+.br
+.ce
+.eo
+Thu Nov 24 18:22:48     81986\n\0
+.ec
+.br
+with five spaces before the year.
+These unusual formats are designed to make it less likely that older
+software that expects exactly 26 bytes of output will mistakenly output
+misleading values for out-of-range years.
+.PP
+The
+.BI * clock
+timestamp represents the time in seconds since 1970-01-01 00:00:00
+Coordinated Universal Time (UTC).
+The POSIX standard says that timestamps must be nonnegative
+and must ignore leap seconds.
+Many implementations extend POSIX by allowing negative timestamps,
+and can therefore represent timestamps that predate the
+introduction of UTC and are some other flavor of Universal Time (UT).
+Some implementations support leap seconds, in contradiction to POSIX.
+.PP
+.I Localtime
+and
+.I gmtime
+return pointers to
+.q "tm"
+structures, described below.
+.I Localtime
+corrects for the time zone and any time zone adjustments
+(such as Daylight Saving Time in the United States).
+After filling in the
+.q "tm"
+structure,
+.I localtime
+sets the
+.BR tm_isdst 'th
+element of
+.B tzname
+to a pointer to a string that's the time zone abbreviation to be used with
+.IR localtime 's
+return value.
+.PP
+.I Gmtime
+converts to Coordinated Universal Time.
+.PP
+.I Asctime
+converts a time value contained in a
+.q "tm"
+structure to a string,
+as shown in the above example,
+and returns a pointer to the string.
+.PP
+.I Mktime
+converts the broken-down time,
+expressed as local time,
+in the structure pointed to by
+.I tm
+into a calendar time value with the same encoding as that of the values
+returned by the
+.I time
+function.
+The original values of the
+.B tm_wday
+and
+.B tm_yday
+components of the structure are ignored,
+and the original values of the other components are not restricted
+to their normal ranges.
+(A positive or zero value for
+.B tm_isdst
+causes
+.I mktime
+to presume initially that daylight saving time
+respectively,
+is or is not in effect for the specified time.
+A negative value for
+.B tm_isdst
+causes the
+.I mktime
+function to attempt to divine whether daylight saving time is in effect
+for the specified time; in this case it does not use a consistent
+rule and may give a different answer when later
+presented with the same argument.)
+On successful completion, the values of the
+.B tm_wday
+and
+.B tm_yday
+components of the structure are set appropriately,
+and the other components are set to represent the specified calendar time,
+but with their values forced to their normal ranges; the final value of
+.B tm_mday
+is not set until
+.B tm_mon
+and
+.B tm_year
+are determined.
+.I Mktime
+returns the specified calendar time;
+If the calendar time cannot be represented,
+it returns \-1.
+.PP
+.I Difftime
+returns the difference between two calendar times,
+.RI ( time1
+\-
+.IR time0 ),
+expressed in seconds.
+.PP
+.IR Ctime_r ,
+.IR localtime_r ,
+.IR gmtime_r ,
+and
+.I asctime_r
+are like their unsuffixed counterparts, except that they accept an
+additional argument specifying where to store the result if successful.
+.PP
+.IR Localtime_rz
+and
+.I mktime_z
+are like their unsuffixed counterparts, except that they accept an
+extra initial
+.B zone
+argument specifying the time zone to be used for conversion.
+If
+.B zone
+is null, UT is used; otherwise,
+.B zone
+should be have been allocated by
+.I tzalloc
+and should not be freed until after all uses (e.g., by calls to
+.IR strftime )
+of the filled-in
+.B tm_zone
+fields.
+.PP
+Declarations of all the functions and externals, and the
+.q "tm"
+structure,
+are in the
+.B <time.h>
+header file.
+The structure (of type)
+.B struct tm
+includes the following fields:
+.RS
+.PP
+.nf
+.ta 2n +\w'long tm_gmtoff;nn'u
+	int tm_sec;	/\(** seconds (0\*(en60) \(**/
+	int tm_min;	/\(** minutes (0\*(en59) \(**/
+	int tm_hour;	/\(** hours (0\*(en23) \(**/
+	int tm_mday;	/\(** day of month (1\*(en31) \(**/
+	int tm_mon;	/\(** month of year (0\*(en11) \(**/
+	int tm_year;	/\(** year \- 1900 \(**/
+	int tm_wday;	/\(** day of week (Sunday = 0) \(**/
+	int tm_yday;	/\(** day of year (0\*(en365) \(**/
+	int tm_isdst;	/\(** is daylight saving time in effect? \(**/
+	char \(**tm_zone;	/\(** time zone abbreviation (optional) \(**/
+	long tm_gmtoff;	/\(** offset from UT in seconds (optional) \(**/
+.fi
+.RE
+.PP
+.I Tm_isdst
+is non-zero if daylight saving time is in effect.
+.PP
+.I Tm_gmtoff
+is the offset (in seconds) of the time represented
+from UT, with positive values indicating east
+of the Prime Meridian.
+The field's name is derived from Greenwich Mean Time, a precursor of UT.
+.PP
+In
+.B struct tm
+the
+.I tm_zone
+and
+.I tm_gmtoff
+fields exist, and are filled in, only if arrangements to do
+so were made when the library containing these functions was
+created.
+Similarly, the
+.B tzname
+variable is optional.
+There is no guarantee that these fields and this variable will
+continue to exist in this form in future releases of this code.
+.SH FILES
+.ta \w'/usr/share/zoneinfo/posixrules\0\0'u
+/usr/share/zoneinfo	time zone information directory
+.br
+/usr/share/zoneinfo/localtime	local time zone file
+.br
+/usr/share/zoneinfo/posixrules	used with POSIX-style TZ's
+.br
+/usr/share/zoneinfo/GMT	for UTC leap seconds
+.sp
+If
+.B /usr/share/zoneinfo/GMT
+is absent,
+UTC leap seconds are loaded from
+.BR /usr/share/zoneinfo/posixrules .
+.SH SEE ALSO
+getenv(3),
+newstrftime(3),
+newtzset(3),
+time(2),
+tzfile(5)
+.SH NOTES
+The return values of
+.IR asctime ,
+.IR ctime ,
+.IR gmtime ,
+and
+.I localtime
+point to static data
+overwritten by each call.
+The
+.B tzname
+variable (once set) and the
+.B tm_zone
+field of a returned
+.B "struct tm"
+both point to an array of characters that
+can be freed or overwritten by later calls to the functions
+.IR localtime ,
+.IR tzfree ,
+and
+.IR tzset ,
+if these functions affect the time zone information that specifies the
+abbreviation in question.
+The remaining functions and data are thread-safe.
+.PP
+.IR Asctime ,
+.IR asctime_r ,
+.IR ctime ,
+and
+.I ctime_r
+behave strangely for years before 1000 or after 9999.
+The 1989 and 1999 editions of the C Standard say
+that years from \-99 through 999 are converted without
+extra spaces, but this conflicts with longstanding
+tradition and with this implementation.
+The 2011 edition says that the behavior
+is undefined if the year is before 1000 or after 9999.
+Traditional implementations of these two functions are
+restricted to years in the range 1900 through 2099.
+To avoid this portability mess, new programs should use
+.I strftime
+instead.
+.\" This file is in the public domain, so clarified as of
+.\" 2009-05-17 by Arthur David Olson.
diff --git a/newctime.3.txt b/newctime.3.txt
new file mode 100644
index 000000000000..2957a6ce9355
--- /dev/null
+++ b/newctime.3.txt
@@ -0,0 +1,171 @@
+NEWCTIME(3)                Library Functions Manual                NEWCTIME(3)
+
+NAME
+       asctime, ctime, difftime, gmtime, localtime, mktime - convert date and
+       time
+
+SYNOPSIS
+       #include <time.h>
+
+       extern char *tzname[]; /* (optional) */
+
+       char *ctime(time_t const *clock);
+
+       char *ctime_r(time_t const *clock, char *buf);
+
+       double difftime(time_t time1, time_t time0);
+
+       char *asctime(struct tm const *tm);
+
+       char *asctime_r(struct tm const *restrict tm,
+           char *restrict result);
+
+       struct tm *localtime(time_t const *clock);
+
+       struct tm *localtime_r(time_t const *restrict clock,
+           struct tm *restrict result);
+
+       struct tm *localtime_rz(timezone_t restrict zone,
+           time_t const *restrict clock,
+           struct tm *restrict result);
+
+       struct tm *gmtime(time_t const *clock);
+
+       struct tm *gmtime_r(time_t const *restrict clock,
+           struct tm *restrict result);
+
+       time_t mktime(struct tm *tm);
+
+       time_t mktime_z(timezone_t restrict zone,
+           struct tm *restrict tm);
+
+       cc ... -ltz
+
+DESCRIPTION
+       Ctime converts a long integer, pointed to by clock, and returns a
+       pointer to a string of the form
+                            Thu Nov 24 18:22:48 1986\n\0
+       Years requiring fewer than four characters are padded with leading
+       zeroes.  For years longer than four characters, the string is of the
+       form
+                          Thu Nov 24 18:22:48     81986\n\0
+       with five spaces before the year.  These unusual formats are designed
+       to make it less likely that older software that expects exactly 26
+       bytes of output will mistakenly output misleading values for out-of-
+       range years.
+
+       The *clock timestamp represents the time in seconds since 1970-01-01
+       00:00:00 Coordinated Universal Time (UTC).  The POSIX standard says
+       that timestamps must be nonnegative and must ignore leap seconds.  Many
+       implementations extend POSIX by allowing negative timestamps, and can
+       therefore represent timestamps that predate the introduction of UTC and
+       are some other flavor of Universal Time (UT).  Some implementations
+       support leap seconds, in contradiction to POSIX.
+
+       Localtime and gmtime return pointers to "tm" structures, described
+       below.  Localtime corrects for the time zone and any time zone
+       adjustments (such as Daylight Saving Time in the United States).  After
+       filling in the "tm" structure, localtime sets the tm_isdst'th element
+       of tzname to a pointer to a string that's the time zone abbreviation to
+       be used with localtime's return value.
+
+       Gmtime converts to Coordinated Universal Time.
+
+       Asctime converts a time value contained in a "tm" structure to a
+       string, as shown in the above example, and returns a pointer to the
+       string.
+
+       Mktime converts the broken-down time, expressed as local time, in the
+       structure pointed to by tm into a calendar time value with the same
+       encoding as that of the values returned by the time function.  The
+       original values of the tm_wday and tm_yday components of the structure
+       are ignored, and the original values of the other components are not
+       restricted to their normal ranges.  (A positive or zero value for
+       tm_isdst causes mktime to presume initially that daylight saving time
+       respectively, is or is not in effect for the specified time.  A
+       negative value for tm_isdst causes the mktime function to attempt to
+       divine whether daylight saving time is in effect for the specified
+       time; in this case it does not use a consistent rule and may give a
+       different answer when later presented with the same argument.)  On
+       successful completion, the values of the tm_wday and tm_yday components
+       of the structure are set appropriately, and the other components are
+       set to represent the specified calendar time, but with their values
+       forced to their normal ranges; the final value of tm_mday is not set
+       until tm_mon and tm_year are determined.  Mktime returns the specified
+       calendar time; If the calendar time cannot be represented, it returns
+       -1.
+
+       Difftime returns the difference between two calendar times, (time1 -
+       time0), expressed in seconds.
+
+       Ctime_r, localtime_r, gmtime_r, and asctime_r are like their unsuffixed
+       counterparts, except that they accept an additional argument specifying
+       where to store the result if successful.
+
+       Localtime_rz and mktime_z are like their unsuffixed counterparts,
+       except that they accept an extra initial zone argument specifying the
+       time zone to be used for conversion.  If zone is null, UT is used;
+       otherwise, zone should be have been allocated by tzalloc and should not
+       be freed until after all uses (e.g., by calls to strftime) of the
+       filled-in tm_zone fields.
+
+       Declarations of all the functions and externals, and the "tm"
+       structure, are in the <time.h> header file.  The structure (of type)
+       struct tm includes the following fields:
+
+                int tm_sec;      /* seconds (0-60) */
+                int tm_min;      /* minutes (0-59) */
+                int tm_hour;     /* hours (0-23) */
+                int tm_mday;     /* day of month (1-31) */
+                int tm_mon;      /* month of year (0-11) */
+                int tm_year;     /* year - 1900 */
+                int tm_wday;     /* day of week (Sunday = 0) */
+                int tm_yday;     /* day of year (0-365) */
+                int tm_isdst;    /* is daylight saving time in effect? */
+                char *tm_zone;   /* time zone abbreviation (optional) */
+                long tm_gmtoff;  /* offset from UT in seconds (optional) */
+
+       Tm_isdst is non-zero if daylight saving time is in effect.
+
+       Tm_gmtoff is the offset (in seconds) of the time represented from UT,
+       with positive values indicating east of the Prime Meridian.  The
+       field's name is derived from Greenwich Mean Time, a precursor of UT.
+
+       In struct tm the tm_zone and tm_gmtoff fields exist, and are filled in,
+       only if arrangements to do so were made when the library containing
+       these functions was created.  Similarly, the tzname variable is
+       optional.  There is no guarantee that these fields and this variable
+       will continue to exist in this form in future releases of this code.
+
+FILES
+       /usr/share/zoneinfo             time zone information directory
+       /usr/share/zoneinfo/localtime   local time zone file
+       /usr/share/zoneinfo/posixrules  used with POSIX-style TZ's
+       /usr/share/zoneinfo/GMT         for UTC leap seconds
+
+       If /usr/share/zoneinfo/GMT is absent, UTC leap seconds are loaded from
+       /usr/share/zoneinfo/posixrules.
+
+SEE ALSO
+       getenv(3), newstrftime(3), newtzset(3), time(2), tzfile(5)
+
+NOTES
+       The return values of asctime, ctime, gmtime, and localtime point to
+       static data overwritten by each call.  The tzname variable (once set)
+       and the tm_zone field of a returned struct tm both point to an array of
+       characters that can be freed or overwritten by later calls to the
+       functions localtime, tzfree, and tzset, if these functions affect the
+       time zone information that specifies the abbreviation in question.  The
+       remaining functions and data are thread-safe.
+
+       Asctime, asctime_r, ctime, and ctime_r behave strangely for years
+       before 1000 or after 9999.  The 1989 and 1999 editions of the C
+       Standard say that years from -99 through 999 are converted without
+       extra spaces, but this conflicts with longstanding tradition and with
+       this implementation.  The 2011 edition says that the behavior is
+       undefined if the year is before 1000 or after 9999.  Traditional
+       implementations of these two functions are restricted to years in the
+       range 1900 through 2099.  To avoid this portability mess, new programs
+       should use strftime instead.
+
+                                                                   NEWCTIME(3)
diff --git a/newstrftime.3 b/newstrftime.3
new file mode 100644
index 000000000000..f1a1a6d7c1cd
--- /dev/null
+++ b/newstrftime.3
@@ -0,0 +1,238 @@
+.\" Based on the UCB file whose corrected copyright information appears below.
+.\" Copyright 1989, 1991 The Regents of the University of California.
+.\" All rights reserved.
+.\"
+.\" This code is derived from software contributed to Berkeley by
+.\" the American National Standards Committee X3, on Information
+.\" Processing Systems.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\" 3. Neither the name of the University nor the names of its contributors
+.\"    may be used to endorse or promote products derived from this software
+.\"    without specific prior written permission.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS" AND
+.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+.\" SUCH DAMAGE.
+.\"
+.\"     from: @(#)strftime.3	5.12 (Berkeley) 6/29/91
+.\"	$Id: strftime.3,v 1.4 1993/12/15 20:33:00 jtc Exp $
+.\"
+.TH NEWSTRFTIME 3
+.SH NAME
+strftime \- format date and time
+.SH SYNOPSIS
+.nf
+.ie \n(.g .ds - \f(CW-\fP
+.el ds - \-
+.B #include <time.h>
+.PP
+.B "size_t strftime(char *restrict buf, size_t maxsize,"
+.B "    char const *restrict format, struct tm const *restrict timeptr);"
+.PP
+.B cc ... \-ltz
+.fi
+.SH DESCRIPTION
+.ie '\(en'' .ds en \-
+.el .ds en \(en
+.ie '\(lq'' .ds lq \&"\"
+.el .ds lq \(lq\"
+.ie '\(rq'' .ds rq \&"\"
+.el .ds rq \(rq\"
+.de q
+\\$3\*(lq\\$1\*(rq\\$2
+..
+The
+.I strftime
+function formats the information from
+.I timeptr
+into the buffer
+.I buf
+according to the string pointed to by
+.IR format .
+.PP
+The
+.I format
+string consists of zero or more conversion specifications and
+ordinary characters.
+All ordinary characters are copied directly into the buffer.
+A conversion specification consists of a percent sign
+.Ql %
+and one other character.
+.PP
+No more than
+.I maxsize
+characters are placed into the array.
+If the total number of resulting characters, including the terminating
+null character, is not more than
+.IR maxsize ,
+.I strftime
+returns the number of characters in the array, not counting the
+terminating null.
+Otherwise, zero is returned.
+.PP
+Each conversion specification is replaced by the characters as
+follows which are then copied into the buffer.
+.TP
+%A
+is replaced by the locale's full weekday name.
+.TP
+%a
+is replaced by the locale's abbreviated weekday name.
+.TP
+%B
+is replaced by the locale's full month name.
+.TP
+%b or %h
+is replaced by the locale's abbreviated month name.
+.TP
+%C
+is replaced by the century (a year divided by 100 and truncated to an integer)
+as a decimal number (00\*(en99).
+.TP
+%c
+is replaced by the locale's appropriate date and time representation.
+.TP
+%D
+is replaced by the date in the format %m/%d/%y.
+.TP
+%d
+is replaced by the day of the month as a decimal number (01\*(en31).
+.TP
+%e
+is replaced by the day of month as a decimal number (1\*(en31);
+single digits are preceded by a blank.
+.TP
+%F
+is replaced by the date in the format %Y\*-%m\*-%d.
+.TP
+%G
+is replaced by the ISO 8601 year with century as a decimal number.
+.TP
+%g
+is replaced by the ISO 8601 year without century as a decimal number (00\*(en99).
+.TP
+%H
+is replaced by the hour (24-hour clock) as a decimal number (00\*(en23).
+.TP
+%I
+is replaced by the hour (12-hour clock) as a decimal number (01\*(en12).
+.TP
+%j
+is replaced by the day of the year as a decimal number (001\*(en366).
+.TP
+%k
+is replaced by the hour (24-hour clock) as a decimal number (0\*(en23);
+single digits are preceded by a blank.
+.TP
+%l
+is replaced by the hour (12-hour clock) as a decimal number (1\*(en12);
+single digits are preceded by a blank.
+.TP
+%M
+is replaced by the minute as a decimal number (00\*(en59).
+.TP
+%m
+is replaced by the month as a decimal number (01\*(en12).
+.TP
+%n
+is replaced by a newline.
+.TP
+%p
+is replaced by the locale's equivalent of either AM or PM.
+.TP
+%R
+is replaced by the time in the format %H:%M.
+.TP
+%r
+is replaced by the locale's representation of 12-hour clock time
+using AM/PM notation.
+.TP
+%S
+is replaced by the second as a decimal number (00\*(en60).
+.TP
+%s
+is replaced by the number of seconds since the Epoch (see newctime(3)).
+.TP
+%T
+is replaced by the time in the format %H:%M:%S.
+.TP
+%t
+is replaced by a tab.
+.TP
+%U
+is replaced by the week number of the year (Sunday as the first day of
+the week) as a decimal number (00\*(en53).
+.TP
+%u
+is replaced by the weekday (Monday as the first day of the week)
+as a decimal number (1\*(en7).
+.TP
+%V
+is replaced by the week number of the year (Monday as the first day of
+the week) as a decimal number (01\*(en53).  If the week containing January
+1 has four or more days in the new year, then it is week 1; otherwise
+it is week 53 of the previous year, and the next week is week 1.
+.TP
+%W
+is replaced by the week number of the year (Monday as the first day of
+the week) as a decimal number (00\*(en53).
+.TP
+%w
+is replaced by the weekday (Sunday as the first day of the week)
+as a decimal number (0\*(en6).
+.TP
+%X
+is replaced by the locale's appropriate time representation.
+.TP
+%x
+is replaced by the locale's appropriate date representation.
+.TP
+%Y
+is replaced by the year with century as a decimal number.
+.TP
+%y
+is replaced by the year without century as a decimal number (00\*(en99).
+.TP
+%Z
+is replaced by the time zone name,
+or by the empty string if this is not determinable.
+.TP
+%z
+is replaced by the offset from the Prime Meridian
+in the format +HHMM or \*-HHMM as appropriate,
+with positive values representing locations east of Greenwich,
+or by the empty string if this is not determinable.
+The numeric time zone \*-0000 is used when the time is Universal Time
+but local time is indeterminate; by convention this is used for
+locations while uninhabited, and corresponds to a zero offset when the
+time zone abbreviation begins with
+.q "\*-" .
+.TP
+%%
+is replaced by a single %.
+.TP
+%+
+is replaced by the date and time in date(1) format.
+.SH SEE ALSO
+date(1),
+getenv(3),
+newctime(3),
+newtzset(3),
+time(2),
+tzfile(5)
diff --git a/newstrftime.3.txt b/newstrftime.3.txt
new file mode 100644
index 000000000000..52daff142abf
--- /dev/null
+++ b/newstrftime.3.txt
@@ -0,0 +1,145 @@
+NEWSTRFTIME(3)             Library Functions Manual             NEWSTRFTIME(3)
+
+NAME
+       strftime - format date and time
+
+SYNOPSIS
+       #include <time.h>
+
+       size_t strftime(char *restrict buf, size_t maxsize,
+           char const *restrict format, struct tm const *restrict timeptr);
+
+       cc ... -ltz
+
+DESCRIPTION
+       The strftime function formats the information from timeptr into the
+       buffer buf according to the string pointed to by format.
+
+       The format string consists of zero or more conversion specifications
+       and ordinary characters.  All ordinary characters are copied directly
+       into the buffer.  A conversion specification consists of a percent sign
+       and one other character.
+
+       No more than maxsize characters are placed into the array.  If the
+       total number of resulting characters, including the terminating null
+       character, is not more than maxsize, strftime returns the number of
+       characters in the array, not counting the terminating null.  Otherwise,
+       zero is returned.
+
+       Each conversion specification is replaced by the characters as follows
+       which are then copied into the buffer.
+
+       %A     is replaced by the locale's full weekday name.
+
+       %a     is replaced by the locale's abbreviated weekday name.
+
+       %B     is replaced by the locale's full month name.
+
+       %b or %h
+              is replaced by the locale's abbreviated month name.
+
+       %C     is replaced by the century (a year divided by 100 and truncated
+              to an integer) as a decimal number (00-99).
+
+       %c     is replaced by the locale's appropriate date and time
+              representation.
+
+       %D     is replaced by the date in the format %m/%d/%y.
+
+       %d     is replaced by the day of the month as a decimal number (01-31).
+
+       %e     is replaced by the day of month as a decimal number (1-31);
+              single digits are preceded by a blank.
+
+       %F     is replaced by the date in the format %Y-%m-%d.
+
+       %G     is replaced by the ISO 8601 year with century as a decimal
+              number.
+
+       %g     is replaced by the ISO 8601 year without century as a decimal
+              number (00-99).
+
+       %H     is replaced by the hour (24-hour clock) as a decimal number
+              (00-23).
+
+       %I     is replaced by the hour (12-hour clock) as a decimal number
+              (01-12).
+
+       %j     is replaced by the day of the year as a decimal number
+              (001-366).
+
+       %k     is replaced by the hour (24-hour clock) as a decimal number
+              (0-23); single digits are preceded by a blank.
+
+       %l     is replaced by the hour (12-hour clock) as a decimal number
+              (1-12); single digits are preceded by a blank.
+
+       %M     is replaced by the minute as a decimal number (00-59).
+
+       %m     is replaced by the month as a decimal number (01-12).
+
+       %n     is replaced by a newline.
+
+       %p     is replaced by the locale's equivalent of either AM or PM.
+
+       %R     is replaced by the time in the format %H:%M.
+
+       %r     is replaced by the locale's representation of 12-hour clock time
+              using AM/PM notation.
+
+       %S     is replaced by the second as a decimal number (00-60).
+
+       %s     is replaced by the number of seconds since the Epoch (see
+              newctime(3)).
+
+       %T     is replaced by the time in the format %H:%M:%S.
+
+       %t     is replaced by a tab.
+
+       %U     is replaced by the week number of the year (Sunday as the first
+              day of the week) as a decimal number (00-53).
+
+       %u     is replaced by the weekday (Monday as the first day of the week)
+              as a decimal number (1-7).
+
+       %V     is replaced by the week number of the year (Monday as the first
+              day of the week) as a decimal number (01-53).  If the week
+              containing January 1 has four or more days in the new year, then
+              it is week 1; otherwise it is week 53 of the previous year, and
+              the next week is week 1.
+
+       %W     is replaced by the week number of the year (Monday as the first
+              day of the week) as a decimal number (00-53).
+
+       %w     is replaced by the weekday (Sunday as the first day of the week)
+              as a decimal number (0-6).
+
+       %X     is replaced by the locale's appropriate time representation.
+
+       %x     is replaced by the locale's appropriate date representation.
+
+       %Y     is replaced by the year with century as a decimal number.
+
+       %y     is replaced by the year without century as a decimal number
+              (00-99).
+
+       %Z     is replaced by the time zone name, or by the empty string if
+              this is not determinable.
+
+       %z     is replaced by the offset from the Prime Meridian in the format
+              +HHMM or -HHMM as appropriate, with positive values representing
+              locations east of Greenwich, or by the empty string if this is
+              not determinable.  The numeric time zone -0000 is used when the
+              time is Universal Time but local time is indeterminate; by
+              convention this is used for locations while uninhabited, and
+              corresponds to a zero offset when the time zone abbreviation
+              begins with "-".
+
+       %%     is replaced by a single %.
+
+       %+     is replaced by the date and time in date(1) format.
+
+SEE ALSO
+       date(1), getenv(3), newctime(3), newtzset(3), time(2), tzfile(5)
+
+                                                                NEWSTRFTIME(3)
diff --git a/newtzset.3 b/newtzset.3
new file mode 100644
index 000000000000..0eab7327e8f5
--- /dev/null
+++ b/newtzset.3
@@ -0,0 +1,344 @@
+.TH NEWTZSET 3
+.SH NAME
+tzset \- initialize time conversion information
+.SH SYNOPSIS
+.nf
+.ie \n(.g .ds - \f(CW-\fP
+.el ds - \-
+.B #include <time.h>
+.PP
+.B timezone_t tzalloc(char const *TZ);
+.PP
+.B void tzfree(timezone_t tz);
+.PP
+.B void tzset(void);
+.PP
+.B cc ... \*-ltz
+.fi
+.SH DESCRIPTION
+.ie '\(en'' .ds en \-
+.el .ds en \(en
+.ie '\(lq'' .ds lq \&"\"
+.el .ds lq \(lq\"
+.ie '\(rq'' .ds rq \&"\"
+.el .ds rq \(rq\"
+.de q
+\\$3\*(lq\\$1\*(rq\\$2
+..
+.I Tzalloc
+allocates and returns a time zone object described by
+.BR TZ .
+If
+.B TZ
+is not a valid time zone description, or if the object cannot be allocated,
+.I tzalloc
+returns a null pointer and sets
+.BR errno .
+.PP
+.I Tzfree
+frees a time zone object
+.BR tz ,
+which should have been successfully allocated by
+.IR tzalloc .
+This invalidates any
+.B tm_zone
+pointers that
+.B tz
+was used to set.
+.PP
+.I Tzset
+acts like
+.BR tzalloc(getenv("TZ")) ,
+except it saves any resulting time zone object into internal
+storage that is accessed by
+.IR localtime ,
+.IR localtime_r ,
+and
+.IR mktime .
+The anonymous shared time zone object is freed by the next call to
+.IR tzset .
+If the implied call to
+.B tzalloc
+fails,
+.I tzset
+falls back on Universal Time (UT).
+.PP
+If
+.B TZ
+is null, the best available approximation to local wall
+clock time, as specified by the
+.IR tzfile (5)-format
+file
+.B localtime
+in the system time conversion information directory, is used.
+If
+.B TZ
+is the empty string,
+UT is used, with the abbreviation "UTC"
+and without leap second correction; please see
+.IR newctime (3)
+for more about UT, UTC, and leap seconds.  If
+.B TZ
+is nonnull and nonempty:
+.IP
+if the value begins with a colon, it is used as a pathname of a file
+from which to read the time conversion information;
+.IP
+if the value does not begin with a colon, it is first used as the
+pathname of a file from which to read the time conversion information,
+and, if that file cannot be read, is used directly as a specification of
+the time conversion information.
+.PP
+When
+.B TZ
+is used as a pathname, if it begins with a slash,
+it is used as an absolute pathname; otherwise,
+it is used as a pathname relative to a system time conversion information
+directory.
+The file must be in the format specified in
+.IR tzfile (5).
+.PP
+When
+.B TZ
+is used directly as a specification of the time conversion information,
+it must have the following syntax (spaces inserted for clarity):
+.IP
+\fIstd\|offset\fR[\fIdst\fR[\fIoffset\fR][\fB,\fIrule\fR]]
+.PP
+Where:
+.RS
+.TP 15
+.IR std " and " dst
+Three or more bytes that are the designation for the standard
+.RI ( std )
+or the alternative
+.RI ( dst ,
+such as daylight saving time)
+time zone.  Only
+.I std
+is required; if
+.I dst
+is missing, then daylight saving time does not apply in this locale.
+Upper- and lowercase letters are explicitly allowed.  Any characters
+except a leading colon
+.RB ( : ),
+digits, comma
+.RB ( , ),
+ASCII minus
+.RB ( \*- ),
+ASCII plus
+.RB ( + ),
+and NUL bytes are allowed.
+Alternatively, a designation can be surrounded by angle brackets
+.B <
+and
+.BR > ;
+in this case, the designation can contain any characters other than
+.B >
+and NUL.
+.TP
+.I offset
+Indicates the value one must add to the local time to arrive at
+Coordinated Universal Time.  The
+.I offset
+has the form:
+.RS
+.IP
+\fIhh\fR[\fB:\fImm\fR[\fB:\fIss\fR]]
+.RE
+.IP
+The minutes
+.RI ( mm )
+and seconds
+.RI ( ss )
+are optional.  The hour
+.RI ( hh )
+is required and may be a single digit.  The
+.I offset
+following
+.I std
+is required.  If no
+.I offset
+follows
+.IR dst ,
+daylight saving time is assumed to be one hour ahead of standard time.  One or
+more digits may be used; the value is always interpreted as a decimal
+number.  The hour must be between zero and 24, and the minutes (and
+seconds) \*(en if present \*(en between zero and 59.  If preceded by a
+.q "\*-" ,
+the time zone shall be east of the Prime Meridian; otherwise it shall be
+west (which may be indicated by an optional preceding
+.q "+" .
+.TP
+.I rule
+Indicates when to change to and back from daylight saving time.  The
+.I rule
+has the form:
+.RS
+.IP
+\fIdate\fB/\fItime\fB,\fIdate\fB/\fItime\fR
+.RE
+.IP
+where the first
+.I date
+describes when the change from standard to daylight saving time occurs and the
+second
+.I date
+describes when the change back happens.  Each
+.I time
+field describes when, in current local time, the change to the other
+time is made.
+As an extension to POSIX, daylight saving is assumed to be in effect
+all year if it begins January 1 at 00:00 and ends December 31 at
+24:00 plus the difference between daylight saving and standard time,
+leaving no room for standard time in the calendar.
+.IP
+The format of
+.I date
+is one of the following:
+.RS
+.TP 10
+.BI J n
+The Julian day
+.I n
+.RI "(1\ \(<=" "\ n\ " "\(<=\ 365).
+Leap days are not counted; that is, in all years \*(en including leap
+years \*(en February 28 is day 59 and March 1 is day 60.  It is
+impossible to explicitly refer to the occasional February 29.
+.TP
+.I n
+The zero-based Julian day
+.RI "(0\ \(<=" "\ n\ " "\(<=\ 365).
+Leap days are counted, and it is possible to refer to February 29.
+.TP
+.BI M m . n . d
+The
+.IR d' th
+day
+.RI "(0\ \(<=" "\ d\ " "\(<=\ 6)
+of week
+.I n
+of month
+.I m
+of the year
+.RI "(1\ \(<=" "\ n\ " "\(<=\ 5,
+.RI "1\ \(<=" "\ m\ " "\(<=\ 12,
+where week 5 means
+.q "the last \fId\fP day in month \fIm\fP"
+which may occur in either the fourth or the fifth week).  Week 1 is the
+first week in which the
+.IR d' th
+day occurs.  Day zero is Sunday.
+.RE
+.IP "" 15
+The
+.I time
+has the same format as
+.I offset
+except that POSIX does not allow a leading sign (\c
+.q "\*-"
+or
+.q "+" ).
+As an extension to POSIX, the hours part of
+.I time
+can range from \-167 through 167; this allows for unusual rules such
+as
+.q "the Saturday before the first Sunday of March" .
+The default, if
+.I time
+is not given, is
+.BR 02:00:00 .
+.RE
+.LP
+Here are some examples of
+.B TZ
+values that directly specify the time zone rules; they use some of the
+extensions to POSIX.
+.TP
+.B EST5
+stands for US Eastern Standard
+Time (EST), 5 hours behind UT, without daylight saving.
+.TP
+.B <+12>\*-12<+13>,M11.1.0,M1.2.1/147
+stands for Fiji time, 12 hours ahead
+of UT, springing forward on November's first Sunday at 02:00, and
+falling back on January's second Monday at 147:00 (i.e., 03:00 on the
+first Sunday on or after January 14).  The abbreviations for standard
+and daylight saving time are
+.q "+12"
+and
+.q "+13".
+.TP
+.B IST\*-2IDT,M3.4.4/26,M10.5.0
+stands for Israel Standard Time (IST) and Israel Daylight Time (IDT),
+2 hours ahead of UT, springing forward on March's fourth
+Thursday at 26:00 (i.e., 02:00 on the first Friday on or after March
+23), and falling back on October's last Sunday at 02:00.
+.TP
+.B <\*-04>4<\*-03>,J1/0,J365/25
+stands for permanent daylight saving time, 3 hours behind UT with
+abbreviation
+.q "\*-03".
+There is a dummy fall-back transition on December 31 at 25:00 daylight
+saving time (i.e., 24:00 standard time, equivalent to January 1 at
+00:00 standard time), and a simultaneous spring-forward transition on
+January 1 at 00:00 standard time, so daylight saving time is in effect
+all year and the initial
+.B <\*-04>
+is a placeholder.
+.TP
+.B <\*-03>3<\*-02>,M3.5.0/\*-2,M10.5.0/\*-1
+stands for time in western Greenland, 3 hours behind UT, where clocks
+follow the EU rules of
+springing forward on March's last Sunday at 01:00 UT (\-02:00 local
+time, i.e., 22:00 the previous day) and falling back on October's last
+Sunday at 01:00 UT (\-01:00 local time, i.e., 23:00 the previous day).
+The abbreviations for standard and daylight saving time are
+.q "\*-03"
+and
+.q "\*-02".
+.PP
+If no
+.I rule
+is present in
+.BR TZ ,
+the rules specified
+by the
+.IR tzfile (5)-format
+file
+.B posixrules
+in the system time conversion information directory are used, with the
+standard and daylight saving time offsets from UT replaced by those specified by
+the
+.I offset
+values in
+.BR TZ .
+.PP
+For compatibility with System V Release 3.1, a semicolon
+.RB ( ; )
+may be used to separate the
+.I rule
+from the rest of the specification.
+.SH FILES
+.ta \w'/usr/share/zoneinfo/posixrules\0\0'u
+/usr/share/zoneinfo	time zone information directory
+.br
+/usr/share/zoneinfo/localtime	local time zone file
+.br
+/usr/share/zoneinfo/posixrules	used with POSIX-style TZ's
+.br
+/usr/share/zoneinfo/GMT	for UTC leap seconds
+.sp
+If
+.B /usr/share/zoneinfo/GMT
+is absent,
+UTC leap seconds are loaded from
+.BR /usr/share/zoneinfo/posixrules .
+.SH SEE ALSO
+getenv(3),
+newctime(3),
+newstrftime(3),
+time(2),
+tzfile(5)
+.\" This file is in the public domain, so clarified as of
+.\" 2009-05-17 by Arthur David Olson.
diff --git a/newtzset.3.txt b/newtzset.3.txt
new file mode 100644
index 000000000000..765e4aaba710
--- /dev/null
+++ b/newtzset.3.txt
@@ -0,0 +1,199 @@
+NEWTZSET(3)                Library Functions Manual                NEWTZSET(3)
+
+NAME
+       tzset - initialize time conversion information
+
+SYNOPSIS
+       #include <time.h>
+
+       timezone_t tzalloc(char const *TZ);
+
+       void tzfree(timezone_t tz);
+
+       void tzset(void);
+
+       cc ... -ltz
+
+DESCRIPTION
+       Tzalloc allocates and returns a time zone object described by TZ.  If
+       TZ is not a valid time zone description, or if the object cannot be
+       allocated, tzalloc returns a null pointer and sets errno.
+
+       Tzfree frees a time zone object tz, which should have been successfully
+       allocated by tzalloc.  This invalidates any tm_zone pointers that tz
+       was used to set.
+
+       Tzset acts like tzalloc(getenv("TZ")), except it saves any resulting
+       time zone object into internal storage that is accessed by localtime,
+       localtime_r, and mktime.  The anonymous shared time zone object is
+       freed by the next call to tzset.  If the implied call to tzalloc fails,
+       tzset falls back on Universal Time (UT).
+
+       If TZ is null, the best available approximation to local wall clock
+       time, as specified by the tzfile(5)-format file localtime in the system
+       time conversion information directory, is used.  If TZ is the empty
+       string, UT is used, with the abbreviation "UTC" and without leap second
+       correction; please see newctime(3) for more about UT, UTC, and leap
+       seconds.  If TZ is nonnull and nonempty:
+
+              if the value begins with a colon, it is used as a pathname of a
+              file from which to read the time conversion information;
+
+              if the value does not begin with a colon, it is first used as
+              the pathname of a file from which to read the time conversion
+              information, and, if that file cannot be read, is used directly
+              as a specification of the time conversion information.
+
+       When TZ is used as a pathname, if it begins with a slash, it is used as
+       an absolute pathname; otherwise, it is used as a pathname relative to a
+       system time conversion information directory.  The file must be in the
+       format specified in tzfile(5).
+
+       When TZ is used directly as a specification of the time conversion
+       information, it must have the following syntax (spaces inserted for
+       clarity):
+
+              stdoffset[dst[offset][,rule]]
+
+       Where:
+
+              std and dst    Three or more bytes that are the designation for
+                             the standard (std) or the alternative (dst, such
+                             as daylight saving time) time zone.  Only std is
+                             required; if dst is missing, then daylight saving
+                             time does not apply in this locale.  Upper- and
+                             lowercase letters are explicitly allowed.  Any
+                             characters except a leading colon (:), digits,
+                             comma (,), ASCII minus (-), ASCII plus (+), and
+                             NUL bytes are allowed.  Alternatively, a
+                             designation can be surrounded by angle brackets <
+                             and >; in this case, the designation can contain
+                             any characters other than > and NUL.
+
+              offset         Indicates the value one must add to the local
+                             time to arrive at Coordinated Universal Time.
+                             The offset has the form:
+
+                                    hh[:mm[:ss]]
+
+                             The minutes (mm) and seconds (ss) are optional.
+                             The hour (hh) is required and may be a single
+                             digit.  The offset following std is required.  If
+                             no offset follows dst, daylight saving time is
+                             assumed to be one hour ahead of standard time.
+                             One or more digits may be used; the value is
+                             always interpreted as a decimal number.  The hour
+                             must be between zero and 24, and the minutes (and
+                             seconds) - if present - between zero and 59.  If
+                             preceded by a "-", the time zone shall be east of
+                             the Prime Meridian; otherwise it shall be west
+                             (which may be indicated by an optional preceding
+                             "+".
+
+              rule           Indicates when to change to and back from
+                             daylight saving time.  The rule has the form:
+
+                                    date/time,date/time
+
+                             where the first date describes when the change
+                             from standard to daylight saving time occurs and
+                             the second date describes when the change back
+                             happens.  Each time field describes when, in
+                             current local time, the change to the other time
+                             is made.  As an extension to POSIX, daylight
+                             saving is assumed to be in effect all year if it
+                             begins January 1 at 00:00 and ends December 31 at
+                             24:00 plus the difference between daylight saving
+                             and standard time, leaving no room for standard
+                             time in the calendar.
+
+                             The format of date is one of the following:
+
+                             Jn        The Julian day n (1 <= n <= 365).  Leap
+                                       days are not counted; that is, in all
+                                       years - including leap years - February
+                                       28 is day 59 and March 1 is day 60.  It
+                                       is impossible to explicitly refer to
+                                       the occasional February 29.
+
+                             n         The zero-based Julian day
+                                       (0 <= n <= 365).  Leap days are
+                                       counted, and it is possible to refer to
+                                       February 29.
+
+                             Mm.n.d    The d'th day (0 <= d <= 6) of week n of
+                                       month m of the year (1 <= n <= 5,
+                                       1 <= m <= 12, where week 5 means "the
+                                       last d day in month m" which may occur
+                                       in either the fourth or the fifth
+                                       week).  Week 1 is the first week in
+                                       which the d'th day occurs.  Day zero is
+                                       Sunday.
+
+                             The time has the same format as offset except
+                             that POSIX does not allow a leading sign ("-" or
+                             "+").  As an extension to POSIX, the hours part
+                             of time can range from -167 through 167; this
+                             allows for unusual rules such as "the Saturday
+                             before the first Sunday of March".  The default,
+                             if time is not given, is 02:00:00.
+
+       Here are some examples of TZ values that directly specify the time zone
+       rules; they use some of the extensions to POSIX.
+
+       EST5   stands for US Eastern Standard Time (EST), 5 hours behind UT,
+              without daylight saving.
+
+       <+12>-12<+13>,M11.1.0,M1.2.1/147
+              stands for Fiji time, 12 hours ahead of UT, springing forward on
+              November's first Sunday at 02:00, and falling back on January's
+              second Monday at 147:00 (i.e., 03:00 on the first Sunday on or
+              after January 14).  The abbreviations for standard and daylight
+              saving time are "+12" and "+13".
+
+       IST-2IDT,M3.4.4/26,M10.5.0
+              stands for Israel Standard Time (IST) and Israel Daylight Time
+              (IDT), 2 hours ahead of UT, springing forward on March's fourth
+              Thursday at 26:00 (i.e., 02:00 on the first Friday on or after
+              March 23), and falling back on October's last Sunday at 02:00.
+
+       <-04>4<-03>,J1/0,J365/25
+              stands for permanent daylight saving time, 3 hours behind UT
+              with abbreviation "-03".  There is a dummy fall-back transition
+              on December 31 at 25:00 daylight saving time (i.e., 24:00
+              standard time, equivalent to January 1 at 00:00 standard time),
+              and a simultaneous spring-forward transition on January 1 at
+              00:00 standard time, so daylight saving time is in effect all
+              year and the initial <-04> is a placeholder.
+
+       <-03>3<-02>,M3.5.0/-2,M10.5.0/-1
+              stands for time in western Greenland, 3 hours behind UT, where
+              clocks follow the EU rules of springing forward on March's last
+              Sunday at 01:00 UT (-02:00 local time, i.e., 22:00 the previous
+              day) and falling back on October's last Sunday at 01:00 UT
+              (-01:00 local time, i.e., 23:00 the previous day).  The
+              abbreviations for standard and daylight saving time are "-03"
+              and "-02".
+
+       If no rule is present in TZ, the rules specified by the
+       tzfile(5)-format file posixrules in the system time conversion
+       information directory are used, with the standard and daylight saving
+       time offsets from UT replaced by those specified by the offset values
+       in TZ.
+
+       For compatibility with System V Release 3.1, a semicolon (;) may be
+       used to separate the rule from the rest of the specification.
+
+FILES
+       /usr/share/zoneinfo             time zone information directory
+       /usr/share/zoneinfo/localtime   local time zone file
+       /usr/share/zoneinfo/posixrules  used with POSIX-style TZ's
+       /usr/share/zoneinfo/GMT         for UTC leap seconds
+
+       If /usr/share/zoneinfo/GMT is absent, UTC leap seconds are loaded from
+       /usr/share/zoneinfo/posixrules.
+
+SEE ALSO
+       getenv(3), newctime(3), newstrftime(3), time(2), tzfile(5)
+
+                                                                   NEWTZSET(3)
diff --git a/private.h b/private.h
new file mode 100644
index 000000000000..641f905e4131
--- /dev/null
+++ b/private.h
@@ -0,0 +1,760 @@
+#ifndef PRIVATE_H
+
+#define PRIVATE_H
+
+/*
+** This file is in the public domain, so clarified as of
+** 1996-06-05 by Arthur David Olson.
+*/
+
+/*
+** This header is for use ONLY with the time conversion code.
+** There is no guarantee that it will remain unchanged,
+** or that it will remain at all.
+** Do NOT copy it to any system include directory.
+** Thank you!
+*/
+
+/*
+** zdump has been made independent of the rest of the time
+** conversion package to increase confidence in the verification it provides.
+** You can use zdump to help in verifying other implementations.
+** To do this, compile with -DUSE_LTZ=0 and link without the tz library.
+*/
+#ifndef USE_LTZ
+# define USE_LTZ 1
+#endif
+
+/* This string was in the Factory zone through version 2016f.  */
+#define GRANDPARENTED	"Local time zone must be set--see zic manual page"
+
+/*
+** Defaults for preprocessor symbols.
+** You can override these in your C compiler options, e.g. '-DHAVE_GETTEXT=1'.
+*/
+
+#ifndef HAVE_DECL_ASCTIME_R
+#define HAVE_DECL_ASCTIME_R 1
+#endif
+
+#if !defined HAVE_GENERIC && defined __has_extension
+# if __has_extension(c_generic_selections)
+#  define HAVE_GENERIC 1
+# else
+#  define HAVE_GENERIC 0
+# endif
+#endif
+/* _Generic is buggy in pre-4.9 GCC.  */
+#if !defined HAVE_GENERIC && defined __GNUC__
+# define HAVE_GENERIC (4 < __GNUC__ + (9 <= __GNUC_MINOR__))
+#endif
+#ifndef HAVE_GENERIC
+# define HAVE_GENERIC (201112 <= __STDC_VERSION__)
+#endif
+
+#ifndef HAVE_GETTEXT
+#define HAVE_GETTEXT		0
+#endif /* !defined HAVE_GETTEXT */
+
+#ifndef HAVE_INCOMPATIBLE_CTIME_R
+#define HAVE_INCOMPATIBLE_CTIME_R	0
+#endif
+
+#ifndef HAVE_LINK
+#define HAVE_LINK		1
+#endif /* !defined HAVE_LINK */
+
+#ifndef HAVE_POSIX_DECLS
+#define HAVE_POSIX_DECLS 1
+#endif
+
+#ifndef HAVE_STDBOOL_H
+#define HAVE_STDBOOL_H (199901 <= __STDC_VERSION__)
+#endif
+
+#ifndef HAVE_STRDUP
+#define HAVE_STRDUP 1
+#endif
+
+#ifndef HAVE_STRTOLL
+#define HAVE_STRTOLL 1
+#endif
+
+#ifndef HAVE_SYMLINK
+#define HAVE_SYMLINK		1
+#endif /* !defined HAVE_SYMLINK */
+
+#ifndef HAVE_SYS_STAT_H
+#define HAVE_SYS_STAT_H		1
+#endif /* !defined HAVE_SYS_STAT_H */
+
+#ifndef HAVE_SYS_WAIT_H
+#define HAVE_SYS_WAIT_H		1
+#endif /* !defined HAVE_SYS_WAIT_H */
+
+#ifndef HAVE_UNISTD_H
+#define HAVE_UNISTD_H		1
+#endif /* !defined HAVE_UNISTD_H */
+
+#ifndef HAVE_UTMPX_H
+#define HAVE_UTMPX_H		1
+#endif /* !defined HAVE_UTMPX_H */
+
+#ifndef NETBSD_INSPIRED
+# define NETBSD_INSPIRED 1
+#endif
+
+#if HAVE_INCOMPATIBLE_CTIME_R
+#define asctime_r _incompatible_asctime_r
+#define ctime_r _incompatible_ctime_r
+#endif /* HAVE_INCOMPATIBLE_CTIME_R */
+
+/* Enable tm_gmtoff, tm_zone, and environ on GNUish systems.  */
+#define _GNU_SOURCE 1
+/* Fix asctime_r on Solaris 11.  */
+#define _POSIX_PTHREAD_SEMANTICS 1
+/* Enable strtoimax on pre-C99 Solaris 11.  */
+#define __EXTENSIONS__ 1
+
+/* To avoid having 'stat' fail unnecessarily with errno == EOVERFLOW,
+   enable large files on GNUish systems ...  */
+#ifndef _FILE_OFFSET_BITS
+# define _FILE_OFFSET_BITS 64
+#endif
+/* ... and on AIX ...  */
+#define _LARGE_FILES 1
+/* ... and enable large inode numbers on Mac OS X 10.5 and later.  */
+#define _DARWIN_USE_64_BIT_INODE 1
+
+/*
+** Nested includes
+*/
+
+/* Avoid clashes with NetBSD by renaming NetBSD's declarations.  */
+#define localtime_rz sys_localtime_rz
+#define mktime_z sys_mktime_z
+#define posix2time_z sys_posix2time_z
+#define time2posix_z sys_time2posix_z
+#define timezone_t sys_timezone_t
+#define tzalloc sys_tzalloc
+#define tzfree sys_tzfree
+#include <time.h>
+#undef localtime_rz
+#undef mktime_z
+#undef posix2time_z
+#undef time2posix_z
+#undef timezone_t
+#undef tzalloc
+#undef tzfree
+
+#include <sys/types.h>	/* for time_t */
+#include <string.h>
+#include <limits.h>	/* for CHAR_BIT et al. */
+#include <stdlib.h>
+
+#include <errno.h>
+
+#ifndef ENAMETOOLONG
+# define ENAMETOOLONG EINVAL
+#endif
+#ifndef ENOTSUP
+# define ENOTSUP EINVAL
+#endif
+#ifndef EOVERFLOW
+# define EOVERFLOW EINVAL
+#endif
+
+#if HAVE_GETTEXT
+#include <libintl.h>
+#endif /* HAVE_GETTEXT */
+
+#if HAVE_UNISTD_H
+#include <unistd.h>	/* for R_OK, and other POSIX goodness */
+#endif /* HAVE_UNISTD_H */
+
+#ifndef HAVE_STRFTIME_L
+# if _POSIX_VERSION < 200809
+#  define HAVE_STRFTIME_L 0
+# else
+#  define HAVE_STRFTIME_L 1
+# endif
+#endif
+
+#ifndef USG_COMPAT
+# ifndef _XOPEN_VERSION
+#  define USG_COMPAT 0
+# else
+#  define USG_COMPAT 1
+# endif
+#endif
+
+#ifndef HAVE_TZNAME
+# if _POSIX_VERSION < 198808 && !USG_COMPAT
+#  define HAVE_TZNAME 0
+# else
+#  define HAVE_TZNAME 1
+# endif
+#endif
+
+#ifndef R_OK
+#define R_OK	4
+#endif /* !defined R_OK */
+
+/* Unlike <ctype.h>'s isdigit, this also works if c < 0 | c > UCHAR_MAX. */
+#define is_digit(c) ((unsigned)(c) - '0' <= 9)
+
+/*
+** Define HAVE_STDINT_H's default value here, rather than at the
+** start, since __GLIBC__ and INTMAX_MAX's values depend on
+** previously-included files.  glibc 2.1 and Solaris 10 and later have
+** stdint.h, even with pre-C99 compilers.
+*/
+#ifndef HAVE_STDINT_H
+#define HAVE_STDINT_H \
+   (199901 <= __STDC_VERSION__ \
+    || 2 < __GLIBC__ + (1 <= __GLIBC_MINOR__)	\
+    || __CYGWIN__ || INTMAX_MAX)
+#endif /* !defined HAVE_STDINT_H */
+
+#if HAVE_STDINT_H
+#include <stdint.h>
+#endif /* !HAVE_STDINT_H */
+
+#ifndef HAVE_INTTYPES_H
+# define HAVE_INTTYPES_H HAVE_STDINT_H
+#endif
+#if HAVE_INTTYPES_H
+# include <inttypes.h>
+#endif
+
+/* Pre-C99 GCC compilers define __LONG_LONG_MAX__ instead of LLONG_MAX.  */
+#ifdef __LONG_LONG_MAX__
+# ifndef LLONG_MAX
+#  define LLONG_MAX __LONG_LONG_MAX__
+# endif
+# ifndef LLONG_MIN
+#  define LLONG_MIN (-1 - LLONG_MAX)
+# endif
+#endif
+
+#ifndef INT_FAST64_MAX
+# ifdef LLONG_MAX
+typedef long long	int_fast64_t;
+#  define INT_FAST64_MIN LLONG_MIN
+#  define INT_FAST64_MAX LLONG_MAX
+# else
+#  if LONG_MAX >> 31 < 0xffffffff
+Please use a compiler that supports a 64-bit integer type (or wider);
+you may need to compile with "-DHAVE_STDINT_H".
+#  endif
+typedef long		int_fast64_t;
+#  define INT_FAST64_MIN LONG_MIN
+#  define INT_FAST64_MAX LONG_MAX
+# endif
+#endif
+
+#ifndef PRIdFAST64
+# if INT_FAST64_MAX == LLONG_MAX
+#  define PRIdFAST64 "lld"
+# else
+#  define PRIdFAST64 "ld"
+# endif
+#endif
+
+#ifndef SCNdFAST64
+# define SCNdFAST64 PRIdFAST64
+#endif
+
+#ifndef INT_FAST32_MAX
+# if INT_MAX >> 31 == 0
+typedef long int_fast32_t;
+#  define INT_FAST32_MAX LONG_MAX
+#  define INT_FAST32_MIN LONG_MIN
+# else
+typedef int int_fast32_t;
+#  define INT_FAST32_MAX INT_MAX
+#  define INT_FAST32_MIN INT_MIN
+# endif
+#endif
+
+#ifndef INTMAX_MAX
+# ifdef LLONG_MAX
+typedef long long intmax_t;
+#  if HAVE_STRTOLL
+#   define strtoimax strtoll
+#  endif
+#  define INTMAX_MAX LLONG_MAX
+#  define INTMAX_MIN LLONG_MIN
+# else
+typedef long intmax_t;
+#  define INTMAX_MAX LONG_MAX
+#  define INTMAX_MIN LONG_MIN
+# endif
+# ifndef strtoimax
+#  define strtoimax strtol
+# endif
+#endif
+
+#ifndef PRIdMAX
+# if INTMAX_MAX == LLONG_MAX
+#  define PRIdMAX "lld"
+# else
+#  define PRIdMAX "ld"
+# endif
+#endif
+
+#ifndef UINT_FAST64_MAX
+# if defined ULLONG_MAX || defined __LONG_LONG_MAX__
+typedef unsigned long long uint_fast64_t;
+# else
+#  if ULONG_MAX >> 31 >> 1 < 0xffffffff
+Please use a compiler that supports a 64-bit integer type (or wider);
+you may need to compile with "-DHAVE_STDINT_H".
+#  endif
+typedef unsigned long	uint_fast64_t;
+# endif
+#endif
+
+#ifndef UINTMAX_MAX
+# if defined ULLONG_MAX || defined __LONG_LONG_MAX__
+typedef unsigned long long uintmax_t;
+# else
+typedef unsigned long uintmax_t;
+# endif
+#endif
+
+#ifndef PRIuMAX
+# if defined ULLONG_MAX || defined __LONG_LONG_MAX__
+#  define PRIuMAX "llu"
+# else
+#  define PRIuMAX "lu"
+# endif
+#endif
+
+#ifndef INT32_MAX
+#define INT32_MAX 0x7fffffff
+#endif /* !defined INT32_MAX */
+#ifndef INT32_MIN
+#define INT32_MIN (-1 - INT32_MAX)
+#endif /* !defined INT32_MIN */
+
+#ifndef SIZE_MAX
+#define SIZE_MAX ((size_t) -1)
+#endif
+
+#if 3 <= __GNUC__
+# define ATTRIBUTE_CONST __attribute__ ((const))
+# define ATTRIBUTE_MALLOC __attribute__ ((__malloc__))
+# define ATTRIBUTE_PURE __attribute__ ((__pure__))
+# define ATTRIBUTE_FORMAT(spec) __attribute__ ((__format__ spec))
+#else
+# define ATTRIBUTE_CONST /* empty */
+# define ATTRIBUTE_MALLOC /* empty */
+# define ATTRIBUTE_PURE /* empty */
+# define ATTRIBUTE_FORMAT(spec) /* empty */
+#endif
+
+#if !defined _Noreturn && __STDC_VERSION__ < 201112
+# if 2 < __GNUC__ + (8 <= __GNUC_MINOR__)
+#  define _Noreturn __attribute__ ((__noreturn__))
+# else
+#  define _Noreturn
+# endif
+#endif
+
+#if __STDC_VERSION__ < 199901 && !defined restrict
+# define restrict /* empty */
+#endif
+
+/*
+** Workarounds for compilers/systems.
+*/
+
+#ifndef EPOCH_LOCAL
+# define EPOCH_LOCAL 0
+#endif
+#ifndef EPOCH_OFFSET
+# define EPOCH_OFFSET 0
+#endif
+#ifndef RESERVE_STD_EXT_IDS
+# define RESERVE_STD_EXT_IDS 0
+#endif
+
+/* If standard C identifiers with external linkage (e.g., localtime)
+   are reserved and are not already being renamed anyway, rename them
+   as if compiling with '-Dtime_tz=time_t'.  */
+#if !defined time_tz && RESERVE_STD_EXT_IDS && USE_LTZ
+# define time_tz time_t
+#endif
+
+/*
+** Compile with -Dtime_tz=T to build the tz package with a private
+** time_t type equivalent to T rather than the system-supplied time_t.
+** This debugging feature can test unusual design decisions
+** (e.g., time_t wider than 'long', or unsigned time_t) even on
+** typical platforms.
+*/
+#if defined time_tz || EPOCH_LOCAL || EPOCH_OFFSET != 0
+# define TZ_TIME_T 1
+#else
+# define TZ_TIME_T 0
+#endif
+
+#if TZ_TIME_T
+# ifdef LOCALTIME_IMPLEMENTATION
+static time_t sys_time(time_t *x) { return time(x); }
+# endif
+
+typedef time_tz tz_time_t;
+
+# undef  ctime
+# define ctime tz_ctime
+# undef  ctime_r
+# define ctime_r tz_ctime_r
+# undef  difftime
+# define difftime tz_difftime
+# undef  gmtime
+# define gmtime tz_gmtime
+# undef  gmtime_r
+# define gmtime_r tz_gmtime_r
+# undef  localtime
+# define localtime tz_localtime
+# undef  localtime_r
+# define localtime_r tz_localtime_r
+# undef  localtime_rz
+# define localtime_rz tz_localtime_rz
+# undef  mktime
+# define mktime tz_mktime
+# undef  mktime_z
+# define mktime_z tz_mktime_z
+# undef  offtime
+# define offtime tz_offtime
+# undef  posix2time
+# define posix2time tz_posix2time
+# undef  posix2time_z
+# define posix2time_z tz_posix2time_z
+# undef  strftime
+# define strftime tz_strftime
+# undef  time
+# define time tz_time
+# undef  time2posix
+# define time2posix tz_time2posix
+# undef  time2posix_z
+# define time2posix_z tz_time2posix_z
+# undef  time_t
+# define time_t tz_time_t
+# undef  timegm
+# define timegm tz_timegm
+# undef  timelocal
+# define timelocal tz_timelocal
+# undef  timeoff
+# define timeoff tz_timeoff
+# undef  tzalloc
+# define tzalloc tz_tzalloc
+# undef  tzfree
+# define tzfree tz_tzfree
+# undef  tzset
+# define tzset tz_tzset
+# undef  tzsetwall
+# define tzsetwall tz_tzsetwall
+# if HAVE_STRFTIME_L
+#  undef  strftime_l
+#  define strftime_l tz_strftime_l
+# endif
+# if HAVE_TZNAME
+#  undef  tzname
+#  define tzname tz_tzname
+# endif
+# if USG_COMPAT
+#  undef  daylight
+#  define daylight tz_daylight
+#  undef  timezone
+#  define timezone tz_timezone
+# endif
+# ifdef ALTZONE
+#  undef  altzone
+#  define altzone tz_altzone
+# endif
+
+char *ctime(time_t const *);
+char *ctime_r(time_t const *, char *);
+double difftime(time_t, time_t) ATTRIBUTE_CONST;
+size_t strftime(char *restrict, size_t, char const *restrict,
+		struct tm const *restrict);
+# if HAVE_STRFTIME_L
+size_t strftime_l(char *restrict, size_t, char const *restrict,
+		  struct tm const *restrict, locale_t);
+# endif
+struct tm *gmtime(time_t const *);
+struct tm *gmtime_r(time_t const *restrict, struct tm *restrict);
+struct tm *localtime(time_t const *);
+struct tm *localtime_r(time_t const *restrict, struct tm *restrict);
+time_t mktime(struct tm *);
+time_t time(time_t *);
+void tzset(void);
+#endif
+
+#if !HAVE_DECL_ASCTIME_R && !defined asctime_r
+extern char *asctime_r(struct tm const *restrict, char *restrict);
+#endif
+
+#ifndef HAVE_DECL_ENVIRON
+# if defined environ || defined __USE_GNU
+#  define HAVE_DECL_ENVIRON 1
+# else
+#  define HAVE_DECL_ENVIRON 0
+# endif
+#endif
+
+#if !HAVE_DECL_ENVIRON
+extern char **environ;
+#endif
+
+#if TZ_TIME_T || !HAVE_POSIX_DECLS
+# if HAVE_TZNAME
+extern char *tzname[];
+# endif
+# if USG_COMPAT
+extern long timezone;
+extern int daylight;
+# endif
+#endif
+
+#ifdef ALTZONE
+extern long altzone;
+#endif
+
+/*
+** The STD_INSPIRED functions are similar, but most also need
+** declarations if time_tz is defined.
+*/
+
+#ifdef STD_INSPIRED
+# if TZ_TIME_T || !defined tzsetwall
+void tzsetwall(void);
+# endif
+# if TZ_TIME_T || !defined offtime
+struct tm *offtime(time_t const *, long);
+# endif
+# if TZ_TIME_T || !defined timegm
+time_t timegm(struct tm *);
+# endif
+# if TZ_TIME_T || !defined timelocal
+time_t timelocal(struct tm *);
+# endif
+# if TZ_TIME_T || !defined timeoff
+time_t timeoff(struct tm *, long);
+# endif
+# if TZ_TIME_T || !defined time2posix
+time_t time2posix(time_t);
+# endif
+# if TZ_TIME_T || !defined posix2time
+time_t posix2time(time_t);
+# endif
+#endif
+
+/* Infer TM_ZONE on systems where this information is known, but suppress
+   guessing if NO_TM_ZONE is defined.  Similarly for TM_GMTOFF.  */
+#if (defined __GLIBC__ \
+     || defined __FreeBSD__ || defined __NetBSD__ || defined __OpenBSD__ \
+     || (defined __APPLE__ && defined __MACH__))
+# if !defined TM_GMTOFF && !defined NO_TM_GMTOFF
+#  define TM_GMTOFF tm_gmtoff
+# endif
+# if !defined TM_ZONE && !defined NO_TM_ZONE
+#  define TM_ZONE tm_zone
+# endif
+#endif
+
+/*
+** Define functions that are ABI compatible with NetBSD but have
+** better prototypes.  NetBSD 6.1.4 defines a pointer type timezone_t
+** and labors under the misconception that 'const timezone_t' is a
+** pointer to a constant.  This use of 'const' is ineffective, so it
+** is not done here.  What we call 'struct state' NetBSD calls
+** 'struct __state', but this is a private name so it doesn't matter.
+*/
+#if NETBSD_INSPIRED
+typedef struct state *timezone_t;
+struct tm *localtime_rz(timezone_t restrict, time_t const *restrict,
+			struct tm *restrict);
+time_t mktime_z(timezone_t restrict, struct tm *restrict);
+timezone_t tzalloc(char const *);
+void tzfree(timezone_t);
+# ifdef STD_INSPIRED
+#  if TZ_TIME_T || !defined posix2time_z
+time_t posix2time_z(timezone_t, time_t) ATTRIBUTE_PURE;
+#  endif
+#  if TZ_TIME_T || !defined time2posix_z
+time_t time2posix_z(timezone_t, time_t) ATTRIBUTE_PURE;
+#  endif
+# endif
+#endif
+
+/*
+** Finally, some convenience items.
+*/
+
+#if HAVE_STDBOOL_H
+# include <stdbool.h>
+#else
+# define true 1
+# define false 0
+# define bool int
+#endif
+
+#define TYPE_BIT(type)	(sizeof (type) * CHAR_BIT)
+#define TYPE_SIGNED(type) (((type) -1) < 0)
+#define TWOS_COMPLEMENT(t) ((t) ~ (t) 0 < 0)
+
+/* Max and min values of the integer type T, of which only the bottom
+   B bits are used, and where the highest-order used bit is considered
+   to be a sign bit if T is signed.  */
+#define MAXVAL(t, b)						\
+  ((t) (((t) 1 << ((b) - 1 - TYPE_SIGNED(t)))			\
+	- 1 + ((t) 1 << ((b) - 1 - TYPE_SIGNED(t)))))
+#define MINVAL(t, b)						\
+  ((t) (TYPE_SIGNED(t) ? - TWOS_COMPLEMENT(t) - MAXVAL(t, b) : 0))
+
+/* The extreme time values, assuming no padding.  */
+#define TIME_T_MIN_NO_PADDING MINVAL(time_t, TYPE_BIT(time_t))
+#define TIME_T_MAX_NO_PADDING MAXVAL(time_t, TYPE_BIT(time_t))
+
+/* The extreme time values.  These are macros, not constants, so that
+   any portability problem occur only when compiling .c files that use
+   the macros, which is safer for applications that need only zdump and zic.
+   This implementation assumes no padding if time_t is signed and
+   either the compiler lacks support for _Generic or time_t is not one
+   of the standard signed integer types.  */
+#if HAVE_GENERIC
+# define TIME_T_MIN \
+    _Generic((time_t) 0, \
+	     signed char: SCHAR_MIN, short: SHRT_MIN, \
+	     int: INT_MIN, long: LONG_MIN, long long: LLONG_MIN, \
+	     default: TIME_T_MIN_NO_PADDING)
+# define TIME_T_MAX \
+    (TYPE_SIGNED(time_t) \
+     ? _Generic((time_t) 0, \
+		signed char: SCHAR_MAX, short: SHRT_MAX, \
+		int: INT_MAX, long: LONG_MAX, long long: LLONG_MAX, \
+		default: TIME_T_MAX_NO_PADDING)			    \
+     : (time_t) -1)
+#else
+# define TIME_T_MIN TIME_T_MIN_NO_PADDING
+# define TIME_T_MAX TIME_T_MAX_NO_PADDING
+#endif
+
+/*
+** 302 / 1000 is log10(2.0) rounded up.
+** Subtract one for the sign bit if the type is signed;
+** add one for integer division truncation;
+** add one more for a minus sign if the type is signed.
+*/
+#define INT_STRLEN_MAXIMUM(type) \
+	((TYPE_BIT(type) - TYPE_SIGNED(type)) * 302 / 1000 + \
+	1 + TYPE_SIGNED(type))
+
+/*
+** INITIALIZE(x)
+*/
+
+#ifdef GCC_LINT
+# define INITIALIZE(x)	((x) = 0)
+#else
+# define INITIALIZE(x)
+#endif
+
+#ifndef UNINIT_TRAP
+# define UNINIT_TRAP 0
+#endif
+
+/*
+** For the benefit of GNU folk...
+** '_(MSGID)' uses the current locale's message library string for MSGID.
+** The default is to use gettext if available, and use MSGID otherwise.
+*/
+
+#if HAVE_GETTEXT
+#define _(msgid) gettext(msgid)
+#else /* !HAVE_GETTEXT */
+#define _(msgid) msgid
+#endif /* !HAVE_GETTEXT */
+
+#if !defined TZ_DOMAIN && defined HAVE_GETTEXT
+# define TZ_DOMAIN "tz"
+#endif
+
+#if HAVE_INCOMPATIBLE_CTIME_R
+#undef asctime_r
+#undef ctime_r
+char *asctime_r(struct tm const *, char *);
+char *ctime_r(time_t const *, char *);
+#endif /* HAVE_INCOMPATIBLE_CTIME_R */
+
+/* Handy macros that are independent of tzfile implementation.  */
+
+#define YEARSPERREPEAT		400	/* years before a Gregorian repeat */
+
+#define SECSPERMIN	60
+#define MINSPERHOUR	60
+#define HOURSPERDAY	24
+#define DAYSPERWEEK	7
+#define DAYSPERNYEAR	365
+#define DAYSPERLYEAR	366
+#define SECSPERHOUR	(SECSPERMIN * MINSPERHOUR)
+#define SECSPERDAY	((int_fast32_t) SECSPERHOUR * HOURSPERDAY)
+#define MONSPERYEAR	12
+
+#define TM_SUNDAY	0
+#define TM_MONDAY	1
+#define TM_TUESDAY	2
+#define TM_WEDNESDAY	3
+#define TM_THURSDAY	4
+#define TM_FRIDAY	5
+#define TM_SATURDAY	6
+
+#define TM_JANUARY	0
+#define TM_FEBRUARY	1
+#define TM_MARCH	2
+#define TM_APRIL	3
+#define TM_MAY		4
+#define TM_JUNE		5
+#define TM_JULY		6
+#define TM_AUGUST	7
+#define TM_SEPTEMBER	8
+#define TM_OCTOBER	9
+#define TM_NOVEMBER	10
+#define TM_DECEMBER	11
+
+#define TM_YEAR_BASE	1900
+
+#define EPOCH_YEAR	1970
+#define EPOCH_WDAY	TM_THURSDAY
+
+#define isleap(y) (((y) % 4) == 0 && (((y) % 100) != 0 || ((y) % 400) == 0))
+
+/*
+** Since everything in isleap is modulo 400 (or a factor of 400), we know that
+**	isleap(y) == isleap(y % 400)
+** and so
+**	isleap(a + b) == isleap((a + b) % 400)
+** or
+**	isleap(a + b) == isleap(a % 400 + b % 400)
+** This is true even if % means modulo rather than Fortran remainder
+** (which is allowed by C89 but not by C99 or later).
+** We use this to avoid addition overflow problems.
+*/
+
+#define isleap_sum(a, b)	isleap((a) % 400 + (b) % 400)
+
+
+/*
+** The Gregorian year averages 365.2425 days, which is 31556952 seconds.
+*/
+
+#define AVGSECSPERYEAR		31556952L
+#define SECSPERREPEAT \
+  ((int_fast64_t) YEARSPERREPEAT * (int_fast64_t) AVGSECSPERYEAR)
+#define SECSPERREPEAT_BITS	34	/* ceil(log2(SECSPERREPEAT)) */
+
+#endif /* !defined PRIVATE_H */
diff --git a/strftime.c b/strftime.c
new file mode 100644
index 000000000000..e85589079172
--- /dev/null
+++ b/strftime.c
@@ -0,0 +1,633 @@
+/* Convert a broken-down timestamp to a string.  */
+
+/* Copyright 1989 The Regents of the University of California.
+   All rights reserved.
+
+   Redistribution and use in source and binary forms, with or without
+   modification, are permitted provided that the following conditions
+   are met:
+   1. Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+   2. Redistributions in binary form must reproduce the above copyright
+      notice, this list of conditions and the following disclaimer in the
+      documentation and/or other materials provided with the distribution.
+   3. Neither the name of the University nor the names of its contributors
+      may be used to endorse or promote products derived from this software
+      without specific prior written permission.
+
+   THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS" AND
+   ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+   IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+   ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+   FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+   DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+   OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+   HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+   LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+   OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+   SUCH DAMAGE.  */
+
+/*
+** Based on the UCB version with the copyright notice appearing above.
+**
+** This is ANSIish only when "multibyte character == plain character".
+*/
+
+#include "private.h"
+
+#include <fcntl.h>
+#include <locale.h>
+#include <stdio.h>
+
+#ifndef DEPRECATE_TWO_DIGIT_YEARS
+# define DEPRECATE_TWO_DIGIT_YEARS false
+#endif
+
+struct lc_time_T {
+	const char *	mon[MONSPERYEAR];
+	const char *	month[MONSPERYEAR];
+	const char *	wday[DAYSPERWEEK];
+	const char *	weekday[DAYSPERWEEK];
+	const char *	X_fmt;
+	const char *	x_fmt;
+	const char *	c_fmt;
+	const char *	am;
+	const char *	pm;
+	const char *	date_fmt;
+};
+
+#define Locale	(&C_time_locale)
+
+static const struct lc_time_T	C_time_locale = {
+	{
+		"Jan", "Feb", "Mar", "Apr", "May", "Jun",
+		"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
+	}, {
+		"January", "February", "March", "April", "May", "June",
+		"July", "August", "September", "October", "November", "December"
+	}, {
+		"Sun", "Mon", "Tue", "Wed",
+		"Thu", "Fri", "Sat"
+	}, {
+		"Sunday", "Monday", "Tuesday", "Wednesday",
+		"Thursday", "Friday", "Saturday"
+	},
+
+	/* X_fmt */
+	"%H:%M:%S",
+
+	/*
+	** x_fmt
+	** C99 and later require this format.
+	** Using just numbers (as here) makes Quakers happier;
+	** it's also compatible with SVR4.
+	*/
+	"%m/%d/%y",
+
+	/*
+	** c_fmt
+	** C99 and later require this format.
+	** Previously this code used "%D %X", but we now conform to C99.
+	** Note that
+	**	"%a %b %d %H:%M:%S %Y"
+	** is used by Solaris 2.3.
+	*/
+	"%a %b %e %T %Y",
+
+	/* am */
+	"AM",
+
+	/* pm */
+	"PM",
+
+	/* date_fmt */
+	"%a %b %e %H:%M:%S %Z %Y"
+};
+
+enum warn { IN_NONE, IN_SOME, IN_THIS, IN_ALL };
+
+static char *	_add(const char *, char *, const char *);
+static char *	_conv(int, const char *, char *, const char *);
+static char *	_fmt(const char *, const struct tm *, char *, const char *,
+		     enum warn *);
+static char *	_yconv(int, int, bool, bool, char *, char const *);
+
+#ifndef YEAR_2000_NAME
+#define YEAR_2000_NAME	"CHECK_STRFTIME_FORMATS_FOR_TWO_DIGIT_YEARS"
+#endif /* !defined YEAR_2000_NAME */
+
+#if HAVE_STRFTIME_L
+size_t
+strftime_l(char *s, size_t maxsize, char const *format, struct tm const *t,
+	   locale_t locale)
+{
+  /* Just call strftime, as only the C locale is supported.  */
+  return strftime(s, maxsize, format, t);
+}
+#endif
+
+size_t
+strftime(char *s, size_t maxsize, const char *format, const struct tm *t)
+{
+	char *	p;
+	enum warn warn = IN_NONE;
+
+	tzset();
+	p = _fmt(format, t, s, s + maxsize, &warn);
+	if (DEPRECATE_TWO_DIGIT_YEARS
+	    && warn != IN_NONE && getenv(YEAR_2000_NAME)) {
+		fprintf(stderr, "\n");
+		fprintf(stderr, "strftime format \"%s\" ", format);
+		fprintf(stderr, "yields only two digits of years in ");
+		if (warn == IN_SOME)
+			fprintf(stderr, "some locales");
+		else if (warn == IN_THIS)
+			fprintf(stderr, "the current locale");
+		else	fprintf(stderr, "all locales");
+		fprintf(stderr, "\n");
+	}
+	if (p == s + maxsize)
+		return 0;
+	*p = '\0';
+	return p - s;
+}
+
+static char *
+_fmt(const char *format, const struct tm *t, char *pt,
+     const char *ptlim, enum warn *warnp)
+{
+	for ( ; *format; ++format) {
+		if (*format == '%') {
+label:
+			switch (*++format) {
+			case '\0':
+				--format;
+				break;
+			case 'A':
+				pt = _add((t->tm_wday < 0 ||
+					t->tm_wday >= DAYSPERWEEK) ?
+					"?" : Locale->weekday[t->tm_wday],
+					pt, ptlim);
+				continue;
+			case 'a':
+				pt = _add((t->tm_wday < 0 ||
+					t->tm_wday >= DAYSPERWEEK) ?
+					"?" : Locale->wday[t->tm_wday],
+					pt, ptlim);
+				continue;
+			case 'B':
+				pt = _add((t->tm_mon < 0 ||
+					t->tm_mon >= MONSPERYEAR) ?
+					"?" : Locale->month[t->tm_mon],
+					pt, ptlim);
+				continue;
+			case 'b':
+			case 'h':
+				pt = _add((t->tm_mon < 0 ||
+					t->tm_mon >= MONSPERYEAR) ?
+					"?" : Locale->mon[t->tm_mon],
+					pt, ptlim);
+				continue;
+			case 'C':
+				/*
+				** %C used to do a...
+				**	_fmt("%a %b %e %X %Y", t);
+				** ...whereas now POSIX 1003.2 calls for
+				** something completely different.
+				** (ado, 1993-05-24)
+				*/
+				pt = _yconv(t->tm_year, TM_YEAR_BASE,
+					    true, false, pt, ptlim);
+				continue;
+			case 'c':
+				{
+				enum warn warn2 = IN_SOME;
+
+				pt = _fmt(Locale->c_fmt, t, pt, ptlim, &warn2);
+				if (warn2 == IN_ALL)
+					warn2 = IN_THIS;
+				if (warn2 > *warnp)
+					*warnp = warn2;
+				}
+				continue;
+			case 'D':
+				pt = _fmt("%m/%d/%y", t, pt, ptlim, warnp);
+				continue;
+			case 'd':
+				pt = _conv(t->tm_mday, "%02d", pt, ptlim);
+				continue;
+			case 'E':
+			case 'O':
+				/*
+				** Locale modifiers of C99 and later.
+				** The sequences
+				**	%Ec %EC %Ex %EX %Ey %EY
+				**	%Od %oe %OH %OI %Om %OM
+				**	%OS %Ou %OU %OV %Ow %OW %Oy
+				** are supposed to provide alternative
+				** representations.
+				*/
+				goto label;
+			case 'e':
+				pt = _conv(t->tm_mday, "%2d", pt, ptlim);
+				continue;
+			case 'F':
+				pt = _fmt("%Y-%m-%d", t, pt, ptlim, warnp);
+				continue;
+			case 'H':
+				pt = _conv(t->tm_hour, "%02d", pt, ptlim);
+				continue;
+			case 'I':
+				pt = _conv((t->tm_hour % 12) ?
+					(t->tm_hour % 12) : 12,
+					"%02d", pt, ptlim);
+				continue;
+			case 'j':
+				pt = _conv(t->tm_yday + 1, "%03d", pt, ptlim);
+				continue;
+			case 'k':
+				/*
+				** This used to be...
+				**	_conv(t->tm_hour % 12 ?
+				**		t->tm_hour % 12 : 12, 2, ' ');
+				** ...and has been changed to the below to
+				** match SunOS 4.1.1 and Arnold Robbins'
+				** strftime version 3.0. That is, "%k" and
+				** "%l" have been swapped.
+				** (ado, 1993-05-24)
+				*/
+				pt = _conv(t->tm_hour, "%2d", pt, ptlim);
+				continue;
+#ifdef KITCHEN_SINK
+			case 'K':
+				/*
+				** After all this time, still unclaimed!
+				*/
+				pt = _add("kitchen sink", pt, ptlim);
+				continue;
+#endif /* defined KITCHEN_SINK */
+			case 'l':
+				/*
+				** This used to be...
+				**	_conv(t->tm_hour, 2, ' ');
+				** ...and has been changed to the below to
+				** match SunOS 4.1.1 and Arnold Robbin's
+				** strftime version 3.0. That is, "%k" and
+				** "%l" have been swapped.
+				** (ado, 1993-05-24)
+				*/
+				pt = _conv((t->tm_hour % 12) ?
+					(t->tm_hour % 12) : 12,
+					"%2d", pt, ptlim);
+				continue;
+			case 'M':
+				pt = _conv(t->tm_min, "%02d", pt, ptlim);
+				continue;
+			case 'm':
+				pt = _conv(t->tm_mon + 1, "%02d", pt, ptlim);
+				continue;
+			case 'n':
+				pt = _add("\n", pt, ptlim);
+				continue;
+			case 'p':
+				pt = _add((t->tm_hour >= (HOURSPERDAY / 2)) ?
+					Locale->pm :
+					Locale->am,
+					pt, ptlim);
+				continue;
+			case 'R':
+				pt = _fmt("%H:%M", t, pt, ptlim, warnp);
+				continue;
+			case 'r':
+				pt = _fmt("%I:%M:%S %p", t, pt, ptlim, warnp);
+				continue;
+			case 'S':
+				pt = _conv(t->tm_sec, "%02d", pt, ptlim);
+				continue;
+			case 's':
+				{
+					struct tm	tm;
+					char		buf[INT_STRLEN_MAXIMUM(
+								time_t) + 1];
+					time_t		mkt;
+
+					tm = *t;
+					mkt = mktime(&tm);
+					if (TYPE_SIGNED(time_t))
+						sprintf(buf, "%"PRIdMAX,
+							(intmax_t) mkt);
+					else	sprintf(buf, "%"PRIuMAX,
+							(uintmax_t) mkt);
+					pt = _add(buf, pt, ptlim);
+				}
+				continue;
+			case 'T':
+				pt = _fmt("%H:%M:%S", t, pt, ptlim, warnp);
+				continue;
+			case 't':
+				pt = _add("\t", pt, ptlim);
+				continue;
+			case 'U':
+				pt = _conv((t->tm_yday + DAYSPERWEEK -
+					t->tm_wday) / DAYSPERWEEK,
+					"%02d", pt, ptlim);
+				continue;
+			case 'u':
+				/*
+				** From Arnold Robbins' strftime version 3.0:
+				** "ISO 8601: Weekday as a decimal number
+				** [1 (Monday) - 7]"
+				** (ado, 1993-05-24)
+				*/
+				pt = _conv((t->tm_wday == 0) ?
+					DAYSPERWEEK : t->tm_wday,
+					"%d", pt, ptlim);
+				continue;
+			case 'V':	/* ISO 8601 week number */
+			case 'G':	/* ISO 8601 year (four digits) */
+			case 'g':	/* ISO 8601 year (two digits) */
+/*
+** From Arnold Robbins' strftime version 3.0: "the week number of the
+** year (the first Monday as the first day of week 1) as a decimal number
+** (01-53)."
+** (ado, 1993-05-24)
+**
+** From <https://www.cl.cam.ac.uk/~mgk25/iso-time.html> by Markus Kuhn:
+** "Week 01 of a year is per definition the first week which has the
+** Thursday in this year, which is equivalent to the week which contains
+** the fourth day of January. In other words, the first week of a new year
+** is the week which has the majority of its days in the new year. Week 01
+** might also contain days from the previous year and the week before week
+** 01 of a year is the last week (52 or 53) of the previous year even if
+** it contains days from the new year. A week starts with Monday (day 1)
+** and ends with Sunday (day 7). For example, the first week of the year
+** 1997 lasts from 1996-12-30 to 1997-01-05..."
+** (ado, 1996-01-02)
+*/
+				{
+					int	year;
+					int	base;
+					int	yday;
+					int	wday;
+					int	w;
+
+					year = t->tm_year;
+					base = TM_YEAR_BASE;
+					yday = t->tm_yday;
+					wday = t->tm_wday;
+					for ( ; ; ) {
+						int	len;
+						int	bot;
+						int	top;
+
+						len = isleap_sum(year, base) ?
+							DAYSPERLYEAR :
+							DAYSPERNYEAR;
+						/*
+						** What yday (-3 ... 3) does
+						** the ISO year begin on?
+						*/
+						bot = ((yday + 11 - wday) %
+							DAYSPERWEEK) - 3;
+						/*
+						** What yday does the NEXT
+						** ISO year begin on?
+						*/
+						top = bot -
+							(len % DAYSPERWEEK);
+						if (top < -3)
+							top += DAYSPERWEEK;
+						top += len;
+						if (yday >= top) {
+							++base;
+							w = 1;
+							break;
+						}
+						if (yday >= bot) {
+							w = 1 + ((yday - bot) /
+								DAYSPERWEEK);
+							break;
+						}
+						--base;
+						yday += isleap_sum(year, base) ?
+							DAYSPERLYEAR :
+							DAYSPERNYEAR;
+					}
+#ifdef XPG4_1994_04_09
+					if ((w == 52 &&
+						t->tm_mon == TM_JANUARY) ||
+						(w == 1 &&
+						t->tm_mon == TM_DECEMBER))
+							w = 53;
+#endif /* defined XPG4_1994_04_09 */
+					if (*format == 'V')
+						pt = _conv(w, "%02d",
+							pt, ptlim);
+					else if (*format == 'g') {
+						*warnp = IN_ALL;
+						pt = _yconv(year, base,
+							false, true,
+							pt, ptlim);
+					} else	pt = _yconv(year, base,
+							true, true,
+							pt, ptlim);
+				}
+				continue;
+			case 'v':
+				/*
+				** From Arnold Robbins' strftime version 3.0:
+				** "date as dd-bbb-YYYY"
+				** (ado, 1993-05-24)
+				*/
+				pt = _fmt("%e-%b-%Y", t, pt, ptlim, warnp);
+				continue;
+			case 'W':
+				pt = _conv((t->tm_yday + DAYSPERWEEK -
+					(t->tm_wday ?
+					(t->tm_wday - 1) :
+					(DAYSPERWEEK - 1))) / DAYSPERWEEK,
+					"%02d", pt, ptlim);
+				continue;
+			case 'w':
+				pt = _conv(t->tm_wday, "%d", pt, ptlim);
+				continue;
+			case 'X':
+				pt = _fmt(Locale->X_fmt, t, pt, ptlim, warnp);
+				continue;
+			case 'x':
+				{
+				enum warn warn2 = IN_SOME;
+
+				pt = _fmt(Locale->x_fmt, t, pt, ptlim, &warn2);
+				if (warn2 == IN_ALL)
+					warn2 = IN_THIS;
+				if (warn2 > *warnp)
+					*warnp = warn2;
+				}
+				continue;
+			case 'y':
+				*warnp = IN_ALL;
+				pt = _yconv(t->tm_year, TM_YEAR_BASE,
+					false, true,
+					pt, ptlim);
+				continue;
+			case 'Y':
+				pt = _yconv(t->tm_year, TM_YEAR_BASE,
+					true, true,
+					pt, ptlim);
+				continue;
+			case 'Z':
+#ifdef TM_ZONE
+				pt = _add(t->TM_ZONE, pt, ptlim);
+#elif HAVE_TZNAME
+				if (t->tm_isdst >= 0)
+					pt = _add(tzname[t->tm_isdst != 0],
+						pt, ptlim);
+#endif
+				/*
+				** C99 and later say that %Z must be
+				** replaced by the empty string if the
+				** time zone is not determinable.
+				*/
+				continue;
+			case 'z':
+#if defined TM_GMTOFF || USG_COMPAT || defined ALTZONE
+				{
+				long		diff;
+				char const *	sign;
+				bool negative;
+
+# ifdef TM_GMTOFF
+				diff = t->TM_GMTOFF;
+# else
+				/*
+				** C99 and later say that the UT offset must
+				** be computed by looking only at
+				** tm_isdst. This requirement is
+				** incorrect, since it means the code
+				** must rely on magic (in this case
+				** altzone and timezone), and the
+				** magic might not have the correct
+				** offset. Doing things correctly is
+				** tricky and requires disobeying the standard;
+				** see GNU C strftime for details.
+				** For now, punt and conform to the
+				** standard, even though it's incorrect.
+				**
+				** C99 and later say that %z must be replaced by
+				** the empty string if the time zone is not
+				** determinable, so output nothing if the
+				** appropriate variables are not available.
+				*/
+				if (t->tm_isdst < 0)
+					continue;
+				if (t->tm_isdst == 0)
+#  if USG_COMPAT
+					diff = -timezone;
+#  else
+					continue;
+#  endif
+				else
+#  ifdef ALTZONE
+					diff = -altzone;
+#  else
+					continue;
+#  endif
+# endif
+				negative = diff < 0;
+				if (diff == 0) {
+#ifdef TM_ZONE
+				  negative = t->TM_ZONE[0] == '-';
+#else
+				  negative = t->tm_isdst < 0;
+# if HAVE_TZNAME
+				  if (tzname[t->tm_isdst != 0][0] == '-')
+				    negative = true;
+# endif
+#endif
+				}
+				if (negative) {
+					sign = "-";
+					diff = -diff;
+				} else	sign = "+";
+				pt = _add(sign, pt, ptlim);
+				diff /= SECSPERMIN;
+				diff = (diff / MINSPERHOUR) * 100 +
+					(diff % MINSPERHOUR);
+				pt = _conv(diff, "%04d", pt, ptlim);
+				}
+#endif
+				continue;
+			case '+':
+				pt = _fmt(Locale->date_fmt, t, pt, ptlim,
+					warnp);
+				continue;
+			case '%':
+			/*
+			** X311J/88-090 (4.12.3.5): if conversion char is
+			** undefined, behavior is undefined. Print out the
+			** character itself as printf(3) also does.
+			*/
+			default:
+				break;
+			}
+		}
+		if (pt == ptlim)
+			break;
+		*pt++ = *format;
+	}
+	return pt;
+}
+
+static char *
+_conv(int n, const char *format, char *pt, const char *ptlim)
+{
+	char	buf[INT_STRLEN_MAXIMUM(int) + 1];
+
+	sprintf(buf, format, n);
+	return _add(buf, pt, ptlim);
+}
+
+static char *
+_add(const char *str, char *pt, const char *ptlim)
+{
+	while (pt < ptlim && (*pt = *str++) != '\0')
+		++pt;
+	return pt;
+}
+
+/*
+** POSIX and the C Standard are unclear or inconsistent about
+** what %C and %y do if the year is negative or exceeds 9999.
+** Use the convention that %C concatenated with %y yields the
+** same output as %Y, and that %Y contains at least 4 bytes,
+** with more only if necessary.
+*/
+
+static char *
+_yconv(int a, int b, bool convert_top, bool convert_yy,
+       char *pt, const char *ptlim)
+{
+	register int	lead;
+	register int	trail;
+
+#define DIVISOR	100
+	trail = a % DIVISOR + b % DIVISOR;
+	lead = a / DIVISOR + b / DIVISOR + trail / DIVISOR;
+	trail %= DIVISOR;
+	if (trail < 0 && lead > 0) {
+		trail += DIVISOR;
+		--lead;
+	} else if (lead < 0 && trail > 0) {
+		trail -= DIVISOR;
+		++lead;
+	}
+	if (convert_top) {
+		if (lead == 0 && trail < 0)
+			pt = _add("-0", pt, ptlim);
+		else	pt = _conv(lead, "%02d", pt, ptlim);
+	}
+	if (convert_yy)
+		pt = _conv(((trail < 0) ? -trail : trail), "%02d", pt, ptlim);
+	return pt;
+}
diff --git a/theory.html b/theory.html
new file mode 100644
index 000000000000..fc2102b3e3c9
--- /dev/null
+++ b/theory.html
@@ -0,0 +1,1304 @@
+<html lang="en">
+<head>
+  <title>Theory and pragmatics of the tz code and data</title>
+  <meta charset="UTF-8">
+</head>
+
+<body>
+<h1>Theory and pragmatics of the <code><abbr>tz</abbr></code> code and data</h1>
+  <h3>Outline</h3>
+  <nav>
+    <ul>
+      <li><a href="#scope">Scope of the <code><abbr>tz</abbr></code>
+	  database</a></li>
+      <li><a href="#naming">Names of time zone rulesets</a></li>
+      <li><a href="#abbreviations">Time zone abbreviations</a></li>
+      <li><a href="#accuracy">Accuracy of the <code><abbr>tz</abbr></code>
+	  database</a></li>
+      <li><a href="#functions">Time and date functions</a></li>
+      <li><a href="#stability">Interface stability</a></li>
+      <li><a href="#calendar">Calendrical issues</a></li>
+      <li><a href="#planets">Time and time zones on other planets</a></li>
+    </ul>
+  </nav>
+
+<section>
+  <h2 id="scope">Scope of the <code><abbr>tz</abbr></code> database</h2>
+<p>
+The <a
+href="https://www.iana.org/time-zones"><code><abbr>tz</abbr></code>
+database</a> attempts to record the history and predicted future of
+all computer-based clocks that track civil time.
+It organizes <a href="tz-link.html">time zone and daylight saving time
+data</a> by partitioning the world into <a
+href="https://en.wikipedia.org/wiki/List_of_tz_database_time_zones">regions</a>
+whose clocks all agree about timestamps that occur after the <a
+href="https://en.wikipedia.org/wiki/Unix_time">POSIX Epoch</a>
+(1970-01-01 00:00:00 <a
+href="https://en.wikipedia.org/wiki/Coordinated_Universal_Time"><abbr
+title="Coordinated Universal Time">UTC</abbr></a>).
+The database labels each such region with a notable location and
+records all known clock transitions for that location.
+Although 1970 is a somewhat-arbitrary cutoff, there are significant
+challenges to moving the cutoff earlier even by a decade or two, due
+to the wide variety of local practices before computer timekeeping
+became prevalent.
+</p>
+
+<p>
+Clock transitions before 1970 are recorded for each such location,
+because most systems support timestamps before 1970 and could
+misbehave if data entries were omitted for pre-1970 transitions.
+However, the database is not designed for and does not suffice for
+applications requiring accurate handling of all past times everywhere,
+as it would take far too much effort and guesswork to record all
+details of pre-1970 civil timekeeping.
+Although some information outside the scope of the database is
+collected in a file <code>backzone</code> that is distributed along
+with the database proper, this file is less reliable and does not
+necessarily follow database guidelines.
+</p>
+
+<p>
+As described below, reference source code for using the
+<code><abbr>tz</abbr></code> database is also available.
+The <code><abbr>tz</abbr></code> code is upwards compatible with <a
+href="https://en.wikipedia.org/wiki/POSIX">POSIX</a>, an international
+standard for <a
+href="https://en.wikipedia.org/wiki/Unix">UNIX</a>-like systems.
+As of this writing, the current edition of POSIX is: <a
+href="http://pubs.opengroup.org/onlinepubs/9699919799/"> The Open
+Group Base Specifications Issue 7</a>, IEEE Std 1003.1-2017, 2018
+Edition.
+Because the database's scope encompasses real-world changes to civil
+timekeeping, its model for describing time is more complex than the
+standard and daylight saving times supported by POSIX.
+A <code><abbr>tz</abbr></code> region corresponds to a ruleset that can
+have more than two changes per year, these changes need not merely
+flip back and forth between two alternatives, and the rules themselves
+can change at times.
+Whether and when a <code><abbr>tz</abbr></code> region changes its
+clock, and even the region's notional base offset from UTC, are variable.
+It does not always make sense to talk about a region's
+"base offset", since it is not necessarily a single number.
+</p>
+
+</section>
+
+<section>
+  <h2 id="naming">Names of time zone rulesets</h2>
+<p>
+Each <code><abbr>tz</abbr></code> region has a unique name that
+corresponds to a set of time zone rules.
+Inexperienced users are not expected to select these names unaided.
+Distributors should provide documentation and/or a simple selection
+interface that explains the names; for one example, see the
+<code>tzselect</code> program in the <code><abbr>tz</abbr></code> code.
+The <a href="http://cldr.unicode.org/">Unicode Common Locale Data
+Repository</a> contains data that may be useful for other selection
+interfaces.
+</p>
+
+<p>
+The naming conventions attempt to strike a balance
+among the following goals:
+</p>
+
+<ul>
+  <li>
+    Uniquely identify every region where clocks have agreed since 1970.
+    This is essential for the intended use: static clocks keeping local
+    civil time.
+  </li>
+  <li>
+    Indicate to experts where that region is.
+  </li>
+  <li>
+    Be robust in the presence of political changes.
+    For example, names of countries are ordinarily not used, to avoid
+    incompatibilities when countries change their name (e.g.,
+    Zaire&rarr;Congo) or when locations change countries (e.g., Hong
+    Kong from UK colony to China).
+  </li>
+  <li>
+    Be portable to a wide variety of implementations.
+  </li>
+  <li>
+    Use a consistent naming conventions over the entire world.
+  </li>
+</ul>
+
+<p>
+Names normally have the form
+<var>AREA</var><code>/</code><var>LOCATION</var>, where
+<var>AREA</var> is the name of a continent or ocean, and
+<var>LOCATION</var> is the name of a specific location within that
+region.
+North and South America share the same area, '<code>America</code>'.
+Typical names are '<code>Africa/Cairo</code>',
+'<code>America/New_York</code>', and '<code>Pacific/Honolulu</code>'.
+Some names are further qualified to help avoid confusion; for example,
+'<code>America/Indiana/Petersburg</code>' distinguishes Petersburg,
+Indiana from other Petersburgs in America.
+</p>
+
+<p>
+Here are the general guidelines used for
+choosing <code><abbr>tz</abbr></code> region names,
+in decreasing order of importance:
+</p>
+
+<ul>
+  <li>
+    Use only valid POSIX file name components (i.e., the parts of
+    names other than '<code>/</code>').
+    Do not use the file name components '<code>.</code>' and
+    '<code>..</code>'.
+    Within a file name component, use only <a
+    href="https://en.wikipedia.org/wiki/ASCII">ASCII</a> letters,
+    '<code>.</code>', '<code>-</code>' and '<code>_</code>'.
+    Do not use digits, as that might create an ambiguity with <a
+    href="http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap08.html#tag_08_03">POSIX
+    <code>TZ</code> strings</a>.
+    A file name component must not exceed 14 characters or start with
+    '<code>-</code>'.
+    E.g., prefer <code>Asia/Brunei</code> to
+    <code>Asia/Bandar_Seri_Begawan</code>.
+    Exceptions: see the discussion of legacy names below.
+  </li>
+  <li>
+    A name must not be empty, or contain '<code>//</code>', or
+    start or end with '<code>/</code>'.
+  </li>
+  <li>
+    Do not use names that differ only in case.
+    Although the reference implementation is case-sensitive, some
+    other implementations are not, and they would mishandle names
+    differing only in case.
+  </li>
+  <li>
+    If one name <var>A</var> is an initial prefix of another
+    name <var>AB</var> (ignoring case), then <var>B</var> must not
+    start with '<code>/</code>', as a regular file cannot have the
+    same name as a directory in POSIX.
+    For example, <code>America/New_York</code> precludes
+    <code>America/New_York/Bronx</code>.
+  </li>
+  <li>
+    Uninhabited regions like the North Pole and Bouvet Island
+    do not need locations, since local time is not defined there.
+  </li>
+  <li>
+    There should typically be at least one name for each <a
+    href="https://en.wikipedia.org/wiki/ISO_3166-1"><abbr
+    title="International Organization for Standardization">ISO</abbr>
+    3166-1</a> officially assigned two-letter code for an inhabited
+    country or territory.
+  </li>
+  <li>
+    If all the clocks in a region have agreed since 1970,
+    do not bother to include more than one location
+    even if subregions' clocks disagreed before 1970.
+    Otherwise these tables would become annoyingly large.
+  </li>
+  <li>
+    If a name is ambiguous, use a less ambiguous alternative;
+    e.g., many cities are named San José and Georgetown, so
+    prefer <code>America/Costa_Rica</code> to
+    <code>America/San_Jose</code> and <code>America/Guyana</code>
+    to <code>America/Georgetown</code>.
+  </li>
+  <li>
+    Keep locations compact.
+    Use cities or small islands, not countries or regions, so that any
+    future changes do not split individual locations into different
+    <code><abbr>tz</abbr></code> regions.
+    E.g., prefer <code>Europe/Paris</code> to <code>Europe/France</code>,
+    since
+    <a href="https://en.wikipedia.org/wiki/Time_in_France#History">France
+    has had multiple time zones</a>.
+  </li>
+  <li>
+    Use mainstream English spelling, e.g., prefer
+    <code>Europe/Rome</code> to <code>Europe/Roma</code>, and
+    prefer <code>Europe/Athens</code> to the Greek
+    <code>Europe/Αθήνα</code> or the Romanized
+    <code>Europe/Athína</code>.
+    The POSIX file name restrictions encourage this guideline.
+  </li>
+  <li>
+    Use the most populous among locations in a region,
+    e.g., prefer <code>Asia/Shanghai</code> to
+    <code>Asia/Beijing</code>.
+    Among locations with similar populations, pick the best-known
+    location, e.g., prefer <code>Europe/Rome</code> to
+    <code>Europe/Milan</code>.
+  </li>
+  <li>
+    Use the singular form, e.g., prefer <code>Atlantic/Canary</code> to
+    <code>Atlantic/Canaries</code>.
+  </li>
+  <li>
+    Omit common suffixes like '<code>_Islands</code>' and
+    '<code>_City</code>', unless that would lead to ambiguity.
+    E.g., prefer <code>America/Cayman</code> to
+    <code>America/Cayman_Islands</code> and
+    <code>America/Guatemala</code> to
+    <code>America/Guatemala_City</code>, but prefer
+    <code>America/Mexico_City</code> to
+    <code>America/Mexico</code>
+    because <a href="https://en.wikipedia.org/wiki/Time_in_Mexico">the
+    country of Mexico has several time zones</a>.
+  </li>
+  <li>
+    Use '<code>_</code>' to represent a space.
+  </li>
+  <li>
+    Omit '<code>.</code>' from abbreviations in names.
+    E.g., prefer <code>Atlantic/St_Helena</code> to
+    <code>Atlantic/St._Helena</code>.
+  </li>
+  <li>
+    Do not change established names if they only marginally violate
+    the above guidelines.
+    For example, do not change the existing name <code>Europe/Rome</code> to
+    <code>Europe/Milan</code> merely because Milan's population has grown
+    to be somewhat greater than Rome's.
+  </li>
+  <li>
+    If a name is changed, put its old spelling in the
+    '<code>backward</code>' file.
+    This means old spellings will continue to work.
+  </li>
+</ul>
+
+<p>
+The file '<code>zone1970.tab</code>' lists geographical locations used
+to name <code><abbr>tz</abbr></code> regions.
+It is intended to be an exhaustive list of names for geographic
+regions as described above; this is a subset of the names in the data.
+Although a '<code>zone1970.tab</code>' location's
+<a href="https://en.wikipedia.org/wiki/Longitude">longitude</a>
+corresponds to
+its <a href="https://en.wikipedia.org/wiki/Local_mean_time">local mean
+time (<abbr>LMT</abbr>)</a> offset with one hour for every 15&deg;
+east longitude, this relationship is not exact.
+</p>
+
+<p>
+Older versions of this package used a different naming scheme,
+and these older names are still supported.
+See the file '<code>backward</code>' for most of these older names
+(e.g., '<code>US/Eastern</code>' instead of '<code>America/New_York</code>').
+The other old-fashioned names still supported are
+'<code>WET</code>', '<code>CET</code>', '<code>MET</code>', and
+'<code>EET</code>' (see the file '<code>europe</code>').
+</p>
+
+<p>
+Older versions of this package defined legacy names that are
+incompatible with the first guideline of location names, but which are
+still supported.
+These legacy names are mostly defined in the file
+'<code>etcetera</code>'.
+Also, the file '<code>backward</code>' defines the legacy names
+'<code>GMT0</code>', '<code>GMT-0</code>' and '<code>GMT+0</code>',
+and the file '<code>northamerica</code>' defines the legacy names
+'<code>EST5EDT</code>', '<code>CST6CDT</code>',
+'<code>MST7MDT</code>', and '<code>PST8PDT</code>'.
+</p>
+
+<p>
+Excluding '<code>backward</code>' should not affect the other data.
+If '<code>backward</code>' is excluded, excluding
+'<code>etcetera</code>' should not affect the remaining data.
+</p>
+</section>
+
+<section>
+  <h2 id="abbreviations">Time zone abbreviations</h2>
+<p>
+When this package is installed, it generates time zone abbreviations
+like '<code>EST</code>' to be compatible with human tradition and POSIX.
+Here are the general guidelines used for choosing time zone abbreviations,
+in decreasing order of importance:
+</p>
+
+<ul>
+  <li>
+    Use three to six characters that are ASCII alphanumerics or
+    '<code>+</code>' or '<code>-</code>'.
+    Previous editions of this database also used characters like
+    space and '<code>?</code>', but these characters have a
+    special meaning to the
+    <a href="https://en.wikipedia.org/wiki/Unix_shell">UNIX shell</a>
+    and cause commands like
+    '<code><a href="http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#set">set</a>
+    `<a href="http://pubs.opengroup.org/onlinepubs/9699919799/utilities/date.html">date</a>`</code>'
+    to have unexpected effects.
+    Previous editions of this guideline required upper-case letters, but the
+    Congressman who introduced
+    <a href="https://en.wikipedia.org/wiki/Chamorro_Time_Zone">Chamorro
+    Standard Time</a> preferred "ChST", so lower-case letters are now
+    allowed.
+    Also, POSIX from 2001 on relaxed the rule to allow '<code>-</code>',
+    '<code>+</code>', and alphanumeric characters from the portable
+    character set in the current locale.
+    In practice ASCII alphanumerics and '<code>+</code>' and
+    '<code>-</code>' are safe in all locales.
+
+    <p>
+    In other words, in the C locale the POSIX extended regular
+    expression <code>[-+[:alnum:]]{3,6}</code> should match the
+    abbreviation.
+    This guarantees that all abbreviations could have been specified by a
+    POSIX <code>TZ</code> string.
+    </p>
+  </li>
+  <li>
+    Use abbreviations that are in common use among English-speakers,
+    e.g., 'EST' for Eastern Standard Time in North America.
+    We assume that applications translate them to other languages
+    as part of the normal localization process; for example,
+    a French application might translate 'EST' to 'HNE'.
+
+    <p>
+    <small>These abbreviations (for standard/daylight/etc. time) are:
+      ACST/ACDT Australian Central,
+      AST/ADT/APT/AWT/ADDT Atlantic,
+      AEST/AEDT Australian Eastern,
+      AHST/AHDT Alaska-Hawaii,
+      AKST/AKDT Alaska,
+      AWST/AWDT Australian Western,
+      BST/BDT Bering,
+      CAT/CAST Central Africa,
+      CET/CEST/CEMT Central European,
+      ChST Chamorro,
+      CST/CDT/CWT/CPT/CDDT Central [North America],
+      CST/CDT China,
+      GMT/BST/IST/BDST Greenwich,
+      EAT East Africa,
+      EST/EDT/EWT/EPT/EDDT Eastern [North America],
+      EET/EEST Eastern European,
+      GST Guam,
+      HST/HDT Hawaii,
+      HKT/HKST Hong Kong,
+      IST India,
+      IST/GMT Irish,
+      IST/IDT/IDDT Israel,
+      JST/JDT Japan,
+      KST/KDT Korea,
+      MET/MEST Middle European (a backward-compatibility alias for
+	Central European),
+      MSK/MSD Moscow,
+      MST/MDT/MWT/MPT/MDDT Mountain,
+      NST/NDT/NWT/NPT/NDDT Newfoundland,
+      NST/NDT/NWT/NPT Nome,
+      NZMT/NZST New Zealand through 1945,
+      NZST/NZDT New Zealand 1946&ndash;present,
+      PKT/PKST Pakistan,
+      PST/PDT/PWT/PPT/PDDT Pacific,
+      SAST South Africa,
+      SST Samoa,
+      WAT/WAST West Africa,
+      WET/WEST/WEMT Western European,
+      WIB Waktu Indonesia Barat,
+      WIT Waktu Indonesia Timur,
+      WITA Waktu Indonesia Tengah,
+      YST/YDT/YWT/YPT/YDDT Yukon</small>.
+    </p>
+  </li>
+  <li>
+    <p>
+    For times taken from a city's longitude, use the
+    traditional <var>x</var>MT notation.
+    The only abbreviation like this in current use is '<abbr>GMT</abbr>'.
+    The others are for timestamps before 1960,
+    except that Monrovia Mean Time persisted until 1972.
+    Typically, numeric abbreviations (e.g., '<code>-</code>004430' for
+    MMT) would cause trouble here, as the numeric strings would exceed
+    the POSIX length limit.
+    </p>
+
+    <p>
+    <small>These abbreviations are:
+      AMT Amsterdam, Asunción, Athens;
+      BMT Baghdad, Bangkok, Batavia, Bern, Bogotá, Bridgetown, Brussels,
+	Bucharest;
+      CMT Calamarca, Caracas, Chisinau, Colón, Copenhagen, Córdoba;
+      DMT Dublin/Dunsink;
+      EMT Easter;
+      FFMT Fort-de-France;
+      FMT Funchal;
+      GMT Greenwich;
+      HMT Havana, Helsinki, Horta, Howrah;
+      IMT Irkutsk, Istanbul;
+      JMT Jerusalem;
+      KMT Kaunas, Kiev, Kingston;
+      LMT Lima, Lisbon, local, Luanda;
+      MMT Macassar, Madras, Malé, Managua, Minsk, Monrovia, Montevideo,
+	Moratuwa, Moscow;
+      PLMT Phù Liễn;
+      PMT Paramaribo, Paris, Perm, Pontianak, Prague;
+      PMMT Port Moresby;
+      QMT Quito;
+      RMT Rangoon, Riga, Rome;
+      SDMT Santo Domingo;
+      SJMT San José;
+      SMT Santiago, Simferopol, Singapore, Stanley;
+      TBMT Tbilisi;
+      TMT Tallinn, Tehran;
+      WMT Warsaw</small>.
+    </p>
+
+    <p>
+    <small>A few abbreviations also follow the pattern that
+    <abbr>GMT<abbr>/<abbr>BST</abbr> established for time in the UK.
+    They are:
+      CMT/BST for Calamarca Mean Time and Bolivian Summer Time
+	1890&ndash;1932,
+      DMT/IST for Dublin/Dunsink Mean Time and Irish Summer Time
+	1880&ndash;1916,
+      MMT/MST/MDST for Moscow 1880&ndash;1919, and
+      RMT/LST for Riga Mean Time and Latvian Summer time 1880&ndash;1926.
+    An extra-special case is SET for Swedish Time (<em>svensk
+    normaltid</em>) 1879&ndash;1899, 3&deg; west of the Stockholm
+    Observatory.</small>
+    </p>
+  </li>
+  <li>
+    Use '<abbr>LMT</abbr>' for local mean time of locations before the
+    introduction of standard time; see "<a href="#scope">Scope of the
+    <code><abbr>tz</abbr></code> database</a>".
+  </li>
+  <li>
+    If there is no common English abbreviation, use numeric offsets like
+    <code>-</code>05 and <code>+</code>0830 that are generated
+    by <code>zic</code>'s <code>%z</code> notation.
+  </li>
+  <li>
+    Use current abbreviations for older timestamps to avoid confusion.
+    For example, in 1910 a common English abbreviation for time
+    in central Europe was 'MEZ' (short for both "Middle European
+    Zone" and for "Mitteleuropäische Zeit" in German).
+    Nowadays 'CET' ("Central European Time") is more common in
+    English, and the database uses 'CET' even for circa-1910
+    timestamps as this is less confusing for modern users and avoids
+    the need for determining when 'CET' supplanted 'MEZ' in common
+    usage.
+  </li>
+  <li>
+    Use a consistent style in a <code><abbr>tz</abbr></code> region's history.
+    For example, if history tends to use numeric
+    abbreviations and a particular entry could go either way, use a
+    numeric abbreviation.
+  </li>
+  <li>
+    Use
+    <a href="https://en.wikipedia.org/wiki/Universal_Time">Universal Time</a>
+    (<abbr>UT</abbr>) (with time zone abbreviation '<code>-</code>00') for
+    locations while uninhabited.
+    The leading '<code>-</code>' is a flag that the <abbr>UT</abbr> offset is in
+    some sense undefined; this notation is derived
+    from <a href="https://tools.ietf.org/html/rfc3339">Internet
+    <abbr title="Request For Comments">RFC 3339</a>.
+  </li>
+</ul>
+
+<p>
+Application writers should note that these abbreviations are ambiguous
+in practice: e.g., 'CST' means one thing in China and something else
+in North America, and 'IST' can refer to time in India, Ireland or
+Israel.
+To avoid ambiguity, use numeric <abbr>UT</abbr> offsets like
+'<code>-</code>0600' instead of time zone abbreviations like 'CST'.
+</p>
+</section>
+
+<section>
+  <h2 id="accuracy">Accuracy of the <code><abbr>tz</abbr></code> database</h2>
+<p>
+The <code><abbr>tz</abbr></code> database is not authoritative, and it
+surely has errors.
+Corrections are welcome and encouraged; see the file <code>CONTRIBUTING</code>.
+Users requiring authoritative data should consult national standards
+bodies and the references cited in the database's comments.
+</p>
+
+<p>
+Errors in the <code><abbr>tz</abbr></code> database arise from many sources:
+</p>
+
+<ul>
+  <li>
+    The <code><abbr>tz</abbr></code> database predicts future
+    timestamps, and current predictions
+    will be incorrect after future governments change the rules.
+    For example, if today someone schedules a meeting for 13:00 next
+    October 1, Casablanca time, and tomorrow Morocco changes its
+    daylight saving rules, software can mess up after the rule change
+    if it blithely relies on conversions made before the change.
+  </li>
+  <li>
+    The pre-1970 entries in this database cover only a tiny sliver of how
+    clocks actually behaved; the vast majority of the necessary
+    information was lost or never recorded.
+    Thousands more <code><abbr>tz</abbr></code> regions would be needed if
+    the <code><abbr>tz</abbr></code> database's scope were extended to
+    cover even just the known or guessed history of standard time; for
+    example, the current single entry for France would need to split
+    into dozens of entries, perhaps hundreds.
+    And in most of the world even this approach would be misleading
+    due to widespread disagreement or indifference about what times
+    should be observed.
+    In her 2015 book
+    <cite><a
+    href="http://www.hup.harvard.edu/catalog.php?isbn=9780674286146">The
+    Global Transformation of Time, 1870&ndash;1950</a></cite>,
+    Vanessa Ogle writes
+    "Outside of Europe and North America there was no system of time
+    zones at all, often not even a stable landscape of mean times,
+    prior to the middle decades of the twentieth century".
+    See: Timothy Shenk, <a
+href="https://www.dissentmagazine.org/blog/booked-a-global-history-of-time-vanessa-ogle">Booked:
+      A Global History of Time</a>. <cite>Dissent</cite> 2015-12-17.
+  </li>
+  <li>
+    Most of the pre-1970 data entries come from unreliable sources, often
+    astrology books that lack citations and whose compilers evidently
+    invented entries when the true facts were unknown, without
+    reporting which entries were known and which were invented.
+    These books often contradict each other or give implausible entries,
+    and on the rare occasions when they are checked they are
+    typically found to be incorrect.
+  </li>
+  <li>
+    For the UK the <code><abbr>tz</abbr></code> database relies on
+    years of first-class work done by
+    Joseph Myers and others; see
+    "<a href="https://www.polyomino.org.uk/british-time/">History of
+    legal time in Britain</a>".
+    Other countries are not done nearly as well.
+  </li>
+  <li>
+    Sometimes, different people in the same city maintain clocks
+    that differ significantly.
+    Historically, railway time was used by railroad companies (which
+    did not always
+    agree with each other), church-clock time was used for birth
+    certificates, etc.
+    More recently, competing political groups might disagree about
+    clock settings. Often this is merely common practice, but
+    sometimes it is set by law.
+    For example, from 1891 to 1911 the <abbr>UT</abbr> offset in France
+    was legally <abbr>UT</abbr> +00:09:21 outside train stations and
+    <abbr>UT</abbr> +00:04:21 inside. Other examples include
+    Chillicothe in 1920, Palm Springs in 1946/7, and Jerusalem and
+    Ürümqi to this day.
+  </li>
+  <li>
+    Although a named location in the <code><abbr>tz</abbr></code>
+    database stands for the containing region, its pre-1970 data
+    entries are often accurate for only a small subset of that region.
+    For example, <code>Europe/London</code> stands for the United
+    Kingdom, but its pre-1847 times are valid only for locations that
+    have London's exact meridian, and its 1847 transition
+    to <abbr>GMT</abbr> is known to be valid only for the L&amp;NW and
+    the Caledonian railways.
+  </li>
+  <li>
+    The <code><abbr>tz</abbr></code> database does not record the
+    earliest time for which a <code><abbr>tz</abbr></code> region's
+    data entries are thereafter valid for every location in the region.
+    For example, <code>Europe/London</code> is valid for all locations
+    in its region after <abbr>GMT</abbr> was made the standard time,
+    but the date of standardization (1880-08-02) is not in the
+    <code><abbr>tz</abbr></code> database, other than in commentary.
+    For many <code><abbr>tz</abbr></code> regions the earliest time of
+    validity is unknown.
+  </li>
+  <li>
+    The <code><abbr>tz</abbr></code> database does not record a
+    region's boundaries, and in many cases the boundaries are not known.
+    For example, the <code><abbr>tz</abbr></code> region
+    <code>America/Kentucky/Louisville</code> represents a region
+    around the city of Louisville, the boundaries of which are
+    unclear.
+  </li>
+  <li>
+    Changes that are modeled as instantaneous transitions in the
+    <code><abbr>tz</abbr></code>
+    database were often spread out over hours, days, or even decades.
+  </li>
+  <li>
+    Even if the time is specified by law, locations sometimes
+    deliberately flout the law.
+  </li>
+  <li>
+    Early timekeeping practices, even assuming perfect clocks, were
+    often not specified to the accuracy that the
+    <code><abbr>tz</abbr></code> database requires.
+  </li>
+  <li>
+    Sometimes historical timekeeping was specified more precisely
+    than what the <code><abbr>tz</abbr></code> code can handle.
+    For example, from 1909 to 1937 <a
+    href="https://www.staff.science.uu.nl/~gent0113/wettijd/wettijd.htm"
+    hreflang="nl">Netherlands clocks</a> were legally Amsterdam Mean
+    Time (estimated to be <abbr>UT</abbr>
+    +00:19:32.13), but the <code><abbr>tz</abbr></code>
+    code cannot represent the fractional second.
+    In practice these old specifications were rarely if ever
+    implemented to subsecond precision.
+  </li>
+  <li>
+    Even when all the timestamp transitions recorded by the
+    <code><abbr>tz</abbr></code> database are correct, the
+    <code><abbr>tz</abbr></code> rules that generate them may not
+    faithfully reflect the historical rules.
+    For example, from 1922 until World War II the UK moved clocks
+    forward the day following the third Saturday in April unless that
+    was Easter, in which case it moved clocks forward the previous
+    Sunday.
+    Because the <code><abbr>tz</abbr></code> database has no
+    way to specify Easter, these exceptional years are entered as
+    separate <code><abbr>tz</abbr> Rule</code> lines, even though the
+    legal rules did not change.
+  </li>
+  <li>
+    The <code><abbr>tz</abbr></code> database models pre-standard time
+    using the <a
+    href="https://en.wikipedia.org/wiki/Proleptic_Gregorian_calendar">proleptic
+    Gregorian calendar</a> and local mean time, but many people used
+    other calendars and other timescales.
+    For example, the Roman Empire used
+    the <a href="https://en.wikipedia.org/wiki/Julian_calendar">Julian
+    calendar</a>,
+    and <a href="https://en.wikipedia.org/wiki/Roman_timekeeping">Roman
+    timekeeping</a> had twelve varying-length daytime hours with a
+    non-hour-based system at night.
+  </li>
+  <li>
+    Early clocks were less reliable, and data entries do not represent
+    clock error.
+  </li>
+  <li>
+    The <code><abbr>tz</abbr></code> database assumes Universal Time
+    (<abbr>UT</abbr>) as an origin, even though <abbr>UT</abbr> is not
+    standardized for older timestamps.
+    In the <code><abbr>tz</abbr></code> database commentary,
+    <abbr>UT</abbr> denotes a family of time standards that includes
+    Coordinated Universal Time (<abbr>UTC</abbr>) along with other
+    variants such as <abbr>UT1</abbr> and <abbr>GMT</abbr>,
+    with days starting at midnight.
+    Although <abbr>UT</abbr> equals <abbr>UTC</abbr> for modern
+    timestamps, <abbr>UTC</abbr> was not defined until 1960, so
+    commentary uses the more-general abbreviation <abbr>UT</abbr> for
+    timestamps that might predate 1960.
+    Since <abbr>UT</abbr>, <abbr>UT1</abbr>, etc. disagree slightly,
+    and since pre-1972 <abbr>UTC</abbr> seconds varied in length,
+    interpretation of older timestamps can be problematic when
+    subsecond accuracy is needed.
+  </li>
+  <li>
+    Civil time was not based on atomic time before 1972, and we do not
+    know the history of
+    <a href="https://en.wikipedia.org/wiki/Earth's_rotation">earth's
+    rotation</a> accurately enough to map <a
+    href="https://en.wikipedia.org/wiki/International_System_of_Units"><abbr
+    title="International System of Units">SI</abbr></a> seconds to
+    historical <a href="https://en.wikipedia.org/wiki/Solar_time">solar time</a>
+    to more than about one-hour accuracy.
+    See: Stephenson FR, Morrison LV, Hohenkerk CY.
+    <a href="http://dx.doi.org/10.1098/rspa.2016.0404">Measurement of
+    the Earth's rotation: 720 BC to AD 2015</a>.
+    <cite>Proc Royal Soc A</cite>. 2016 Dec 7;472:20160404.
+    Also see: Espenak F. <a
+    href="https://eclipse.gsfc.nasa.gov/SEhelp/uncertainty2004.html">Uncertainty
+    in Delta T (ΔT)</a>.
+  </li>
+  <li>
+    The relationship between POSIX time (that is, <abbr>UTC</abbr> but
+    ignoring <a href="https://en.wikipedia.org/wiki/Leap_second">leap
+    seconds</a>) and <abbr>UTC</abbr> is not agreed upon after 1972.
+    Although the POSIX
+    clock officially stops during an inserted leap second, at least one
+    proposed standard has it jumping back a second instead; and in
+    practice POSIX clocks more typically either progress glacially during
+    a leap second, or are slightly slowed while near a leap second.
+  </li>
+  <li>
+    The <code><abbr>tz</abbr></code> database does not represent how
+    uncertain its information is.
+    Ideally it would contain information about when data entries are
+    incomplete or dicey.
+    Partial temporal knowledge is a field of active research, though,
+    and it is not clear how to apply it here.
+  </li>
+</ul>
+
+<p>
+In short, many, perhaps most, of the <code><abbr>tz</abbr></code>
+database's pre-1970 and future timestamps are either wrong or
+misleading.
+Any attempt to pass the
+<code><abbr>tz</abbr></code> database off as the definition of time
+should be unacceptable to anybody who cares about the facts.
+In particular, the <code><abbr>tz</abbr></code> database's
+<abbr>LMT</abbr> offsets should not be considered meaningful, and
+should not prompt creation of <code><abbr>tz</abbr></code> regions
+merely because two locations
+differ in <abbr>LMT</abbr> or transitioned to standard time at
+different dates.
+</p>
+</section>
+
+<section>
+  <h2 id="functions">Time and date functions</h2>
+<p>
+The <code><abbr>tz</abbr></code> code contains time and date functions
+that are upwards compatible with those of POSIX.
+Code compatible with this package is already
+<a href="tz-link.html#tzdb">part of many platforms</a>, where the
+primary use of this package is to update obsolete time-related files.
+To do this, you may need to compile the time zone compiler
+'<code>zic</code>' supplied with this package instead of using the
+system '<code>zic</code>', since the format of <code>zic</code>'s
+input is occasionally extended, and a platform may still be shipping
+an older <code>zic</code>.
+</p>
+
+<h3 id="POSIX">POSIX properties and limitations</h3>
+<ul>
+  <li>
+    <p>
+    In POSIX, time display in a process is controlled by the
+    environment variable <code>TZ</code>.
+    Unfortunately, the POSIX
+    <code>TZ</code> string takes a form that is hard to describe and
+    is error-prone in practice.
+    Also, POSIX <code>TZ</code> strings cannot deal with daylight
+    saving time rules not based on the Gregorian calendar (as in
+    Iran), or with situations where more than two time zone
+    abbreviations or <abbr>UT</abbr> offsets are used in an area.
+    </p>
+
+    <p>
+    The POSIX <code>TZ</code> string takes the following form:
+    </p>
+
+    <p>
+    <var>stdoffset</var>[<var>dst</var>[<var>offset</var>][<code>,</code><var>date</var>[<code>/</code><var>time</var>]<code>,</code><var>date</var>[<code>/</code><var>time</var>]]]
+    </p>
+
+    <p>
+    where:
+    </p>
+
+    <dl>
+      <dt><var>std</var> and <var>dst</var></dt><dd>
+	are 3 or more characters specifying the standard
+	and daylight saving time (<abbr>DST</abbr>) zone names.
+	Starting with POSIX.1-2001, <var>std</var> and <var>dst</var>
+	may also be in a quoted form like '<code>&lt;+09&gt;</code>';
+	this allows "<code>+</code>" and "<code>-</code>" in the names.
+      </dd>
+      <dt><var>offset</var></dt><dd>
+	is of the form
+	'<code>[&plusmn;]<var>hh</var>:[<var>mm</var>[:<var>ss</var>]]</code>'
+	and specifies the offset west of <abbr>UT</abbr>.
+	'<var>hh</var>' may be a single digit;
+	0&le;<var>hh</var>&le;24.
+	The default <abbr>DST</abbr> offset is one hour ahead of
+	standard time.
+      </dd>
+      <dt><var>date</var>[<code>/</code><var>time</var>]<code>,</code><var>date</var>[<code>/</code><var>time</var>]</dt><dd>
+	specifies the beginning and end of <abbr>DST</abbr>.
+	If this is absent, the system supplies its own ruleset
+	for <abbr>DST</abbr>, and its rules can differ from year to year;
+	typically <abbr>US</abbr> <abbr>DST</abbr> rules are used.
+      </dd>
+      <dt><var>time</var></dt><dd>
+	takes the form
+	'<var>hh</var><code>:</code>[<var>mm</var>[<code>:</code><var>ss</var>]]'
+	and defaults to 02:00.
+	This is the same format as the offset, except that a
+	leading '<code>+</code>' or '<code>-</code>' is not allowed.
+      </dd>
+      <dt><var>date</var></dt><dd>
+	takes one of the following forms:
+	<dl>
+	  <dt>J<var>n</var> (1&le;<var>n</var>&le;365)</dt><dd>
+	    origin-1 day number not counting February 29
+	  </dd>
+	  <dt><var>n</var> (0&le;<var>n</var>&le;365)</dt><dd>
+	    origin-0 day number counting February 29 if present
+	  </dd>
+	  <dt><code>M</code><var>m</var><code>.</code><var>n</var><code>.</code><var>d</var>
+	    (0[Sunday]&le;<var>d</var>&le;6[Saturday], 1&le;<var>n</var>&le;5,
+	    1&le;<var>m</var>&le;12)</dt><dd>
+	    for the <var>d</var>th day of week <var>n</var> of
+	    month <var>m</var> of the year, where week 1 is the first
+	    week in which day <var>d</var> appears, and
+	    '<code>5</code>' stands for the last week in which
+	    day <var>d</var> appears (which may be either the 4th or
+	    5th week).
+	    Typically, this is the only useful form; the <var>n</var>
+	    and <code>J</code><var>n</var> forms are rarely used.
+	  </dd>
+	</dl>
+      </dd>
+    </dl>
+
+    <p>
+    Here is an example POSIX <code>TZ</code> string for New
+    Zealand after 2007.
+    It says that standard time (<abbr>NZST</abbr>) is 12 hours ahead
+    of <abbr>UT</abbr>, and that daylight saving time
+    (<abbr>NZDT</abbr>) is observed from September's last Sunday at
+    02:00 until April's first Sunday at 03:00:
+    </p>
+
+    <pre><code>TZ='NZST-12NZDT,M9.5.0,M4.1.0/3'</code></pre>
+
+    <p>
+    This POSIX <code>TZ</code> string is hard to remember, and
+    mishandles some timestamps before 2008.
+    With this package you can use this instead:
+    </p>
+
+    <pre><code>TZ='Pacific/Auckland'</code></pre>
+  </li>
+  <li>
+    POSIX does not define the exact meaning of <code>TZ</code> values like
+    "<code>EST5EDT</code>".
+    Typically the current <abbr>US</abbr> <abbr>DST</abbr> rules
+    are used to interpret such values, but this means that the
+    <abbr>US</abbr> <abbr>DST</abbr> rules are compiled into each
+    program that does time conversion.
+    This means that when
+    <abbr>US</abbr> time conversion rules change (as in the United
+    States in 1987), all programs that do time conversion must be
+    recompiled to ensure proper results.
+  </li>
+  <li>
+    The <code>TZ</code> environment variable is process-global, which
+    makes it hard to write efficient, thread-safe applications that
+    need access to multiple time zone rulesets.
+  </li>
+  <li>
+    In POSIX, there is no tamper-proof way for a process to learn the
+    system's best idea of local wall clock.
+    (This is important for applications that an administrator wants
+    used only at certain times &ndash; without regard to whether the
+    user has fiddled the
+    <code>TZ</code> environment variable.
+    While an administrator can "do everything in <abbr>UT</abbr>" to
+    get around the problem, doing so is inconvenient and precludes
+    handling daylight saving time shifts - as might be required to
+    limit phone calls to off-peak hours.)
+  </li>
+  <li>
+    POSIX provides no convenient and efficient way to determine
+    the <abbr>UT</abbr> offset and time zone abbreviation of arbitrary
+    timestamps, particularly for <code><abbr>tz</abbr></code> regions
+    that do not fit into the POSIX model.
+  </li>
+  <li>
+    POSIX requires that systems ignore leap seconds.
+  </li>
+  <li>
+    The <code><abbr>tz</abbr></code> code attempts to support all the
+    <code>time_t</code> implementations allowed by POSIX.
+    The <code>time_t</code> type represents a nonnegative count of seconds
+    since 1970-01-01 00:00:00 <abbr>UTC</abbr>, ignoring leap seconds.
+    In practice, <code>time_t</code> is usually a signed 64- or 32-bit
+    integer; 32-bit signed <code>time_t</code> values stop working after
+    2038-01-19 03:14:07 <abbr>UTC</abbr>, so new implementations these
+    days typically use a signed 64-bit integer.
+    Unsigned 32-bit integers are used on one or two platforms, and 36-bit
+    and 40-bit integers are also used occasionally.
+    Although earlier POSIX versions allowed <code>time_t</code> to be a
+    floating-point type, this was not supported by any practical systems,
+    and POSIX.1-2013 and the <code><abbr>tz</abbr></code> code both
+    require <code>time_t</code> to be an integer type.
+  </li>
+</ul>
+
+<h3 id="POSIX-extensions">Extensions to POSIX in the
+<code><abbr>tz</abbr></code> code</h3>
+<ul>
+  <li>
+    <p>
+    The <code>TZ</code> environment variable is used in generating
+    the name of a binary file from which time-related information is read
+    (or is interpreted à la POSIX); <code>TZ</code> is no longer
+    constrained to be a three-letter time zone
+    abbreviation followed by a number of hours and an optional three-letter
+    daylight time zone abbreviation.
+    The daylight saving time rules to be used for a
+    particular <code><abbr>tz</abbr></code> region are encoded in the
+    binary file; the format of the file
+    allows U.S., Australian, and other rules to be encoded, and
+    allows for situations where more than two time zone
+    abbreviations are used.
+    </p>
+    <p>
+    It was recognized that allowing the <code>TZ</code> environment
+    variable to take on values such as '<code>America/New_York</code>'
+    might cause "old" programs (that expect <code>TZ</code> to have a
+    certain form) to operate incorrectly; consideration was given to using
+    some other environment variable (for example, <code>TIMEZONE</code>)
+    to hold the string used to generate the binary file's name.
+    In the end, however, it was decided to continue using
+    <code>TZ</code>: it is widely used for time zone purposes;
+    separately maintaining both <code>TZ</code>
+    and <code>TIMEZONE</code> seemed a nuisance; and systems where
+    "new" forms of <code>TZ</code> might cause problems can simply
+    use <code>TZ</code> values such as "<code>EST5EDT</code>" which
+    can be used both by "new" programs (à la POSIX) and "old"
+    programs (as zone names and offsets).
+    </p>
+  </li>
+  <li>
+    The code supports platforms with a <abbr>UT</abbr> offset member
+    in <code>struct tm</code>, e.g., <code>tm_gmtoff</code>.
+  </li>
+  <li>
+    The code supports platforms with a time zone abbreviation member in
+    <code>struct tm</code>, e.g., <code>tm_zone</code>.
+  </li>
+  <li>
+    Functions <code>tzalloc</code>, <code>tzfree</code>,
+    <code>localtime_rz</code>, and <code>mktime_z</code> for
+    more-efficient thread-safe applications that need to use multiple
+    time zone rulesets.
+    The <code>tzalloc</code> and <code>tzfree</code> functions
+    allocate and free objects of type <code>timezone_t</code>,
+    and <code>localtime_rz</code> and <code>mktime_z</code> are
+    like <code>localtime_r</code> and <code>mktime</code> with an
+    extra <code>timezone_t</code> argument.
+    The functions were inspired by <a href="https://netbsd.org/">NetBSD</a>.
+  </li>
+  <li>
+    A function <code>tzsetwall</code> has been added to arrange for the
+    system's best approximation to local wall clock time to be delivered
+    by subsequent calls to <code>localtime</code>.
+    Source code for portable applications that "must" run on local wall
+    clock time should call <code>tzsetwall</code>;
+    if such code is moved to "old" systems that do not
+    provide <code>tzsetwall</code>, you will not be able to generate an
+    executable program.
+    (These functions also arrange for local wall clock time to
+    be used if <code>tzset</code> is called &ndash; directly or
+    indirectly &ndash; and there is no <code>TZ</code> environment
+    variable; portable applications should not, however, rely on this
+    behavior since it is not the way <a
+    href="https://en.wikipedia.org/wiki/UNIX_System_V#SVR2"><abbr>SVR2</abbr></a>
+    systems behave.)
+  </li>
+  <li>
+    Negative <code>time_t</code> values are supported, on systems
+    where <code>time_t</code> is signed.
+  </li>
+  <li>
+    These functions can account for leap seconds, thanks to Bradley White.
+  </li>
+</ul>
+
+<h3 id="vestigial">POSIX features no longer needed</h3>
+<p>
+POSIX and <a href="https://en.wikipedia.org/wiki/ISO_C"><abbr>ISO</abbr> C</a>
+define some <a href="https://en.wikipedia.org/wiki/API"><abbr
+title="application programming interface">API</abbr>s</a> that are vestigial:
+they are not needed, and are relics of a too-simple model that does
+not suffice to handle many real-world timestamps.
+Although the <code><abbr>tz</abbr></code> code supports these
+vestigial <abbr>API</abbr>s for backwards compatibility, they should
+be avoided in portable applications.
+The vestigial <abbr>API</abbr>s are:
+</p>
+<ul>
+  <li>
+    The POSIX <code>tzname</code> variable does not suffice and is no
+    longer needed.
+    To get a timestamp's time zone abbreviation, consult
+    the <code>tm_zone</code> member if available; otherwise,
+    use <code>strftime</code>'s <code>"%Z"</code> conversion
+    specification.
+  </li>
+  <li>
+    The POSIX <code>daylight</code> and <code>timezone</code>
+    variables do not suffice and are no longer needed.
+    To get a timestamp's <abbr>UT</abbr> offset, consult
+    the <code>tm_gmtoff</code> member if available; otherwise,
+    subtract values returned by <code>localtime</code>
+    and <code>gmtime</code> using the rules of the Gregorian calendar,
+    or use <code>strftime</code>'s <code>"%z"</code> conversion
+    specification if a string like <code>"+0900"</code> suffices.
+  </li>
+  <li>
+    The <code>tm_isdst</code> member is almost never needed and most of
+    its uses should be discouraged in favor of the abovementioned
+    <abbr>API</abbr>s.
+    Although it can still be used in arguments to
+    <code>mktime</code> to disambiguate timestamps near
+    a <abbr>DST</abbr> transition when the clock jumps back, this
+    disambiguation does not work when standard time itself jumps back,
+    which can occur when a location changes to a time zone with a
+    lesser <abbr>UT</abbr> offset.
+  </li>
+</ul>
+
+<h3 id="other-portability">Other portability notes</h3>
+<ul>
+  <li>
+    The <a href="https://en.wikipedia.org/wiki/Version_7_Unix">7th Edition
+    UNIX</a> <code>timezone</code> function is not present in this
+    package; it is impossible to reliably map <code>timezone</code>'s
+    arguments (a "minutes west of <abbr>GMT</abbr>" value and a
+    "daylight saving time in effect" flag) to a time zone
+    abbreviation, and we refuse to guess.
+    Programs that in the past used the <code>timezone</code> function
+    may now examine <code>localtime(&amp;clock)-&gt;tm_zone</code>
+    (if <code>TM_ZONE</code> is defined) or
+    <code>tzname[localtime(&amp;clock)-&gt;tm_isdst]</code>
+    (if <code>HAVE_TZNAME</code> is defined) to learn the correct time
+    zone abbreviation to use.
+  </li>
+  <li>
+    The <a
+    href="https://en.wikipedia.org/wiki/History_of_the_Berkeley_Software_Distribution#4.2BSD"><abbr>4.2BSD</abbr></a>
+    <code>gettimeofday</code> function is not
+    used in this package.
+    This formerly let users obtain the current <abbr>UTC</abbr> offset
+    and <abbr>DST</abbr> flag, but this functionality was removed in
+    later versions of <abbr>BSD</abbr>.
+  </li>
+  <li>
+    In <abbr>SVR2</abbr>, time conversion fails for near-minimum or
+    near-maximum <code>time_t</code> values when doing conversions
+    for places that do not use <abbr>UT</abbr>.
+    This package takes care to do these conversions correctly.
+    A comment in the source code tells how to get compatibly wrong
+    results.
+  </li>
+  <li>
+    The functions that are conditionally compiled
+    if <code>STD_INSPIRED</code> is defined should, at this point, be
+    looked on primarily as food for thought.
+    They are not in any sense "standard compatible" &ndash; some are
+    not, in fact, specified in <em>any</em> standard.
+    They do, however, represent responses of various authors to
+    standardization proposals.
+  </li>
+  <li>
+    Other time conversion proposals, in particular the one developed
+    by folks at Hewlett Packard, offer a wider selection of functions
+    that provide capabilities beyond those provided here.
+    The absence of such functions from this package is not meant to
+    discourage the development, standardization, or use of such
+    functions.
+    Rather, their absence reflects the decision to make this package
+    contain valid extensions to POSIX, to ensure its broad
+    acceptability.
+    If more powerful time conversion functions can be standardized, so
+    much the better.
+  </li>
+</ul>
+</section>
+
+<section>
+  <h2 id="stability">Interface stability</h2>
+<p>
+The <code><abbr>tz</abbr></code> code and data supply the following interfaces:
+</p>
+
+<ul>
+  <li>
+    A set of <code><abbr>tz</abbr></code> region names as per
+      "<a href="#naming">Names of time zone rulesets</a>" above.
+  </li>
+  <li>
+    Library functions described in "<a href="#functions">Time and date
+      functions</a>" above.
+  </li>
+  <li>
+    The programs <code>tzselect</code>, <code>zdump</code>,
+    and <code>zic</code>, documented in their man pages.
+  </li>
+  <li>
+    The format of <code>zic</code> input files, documented in
+    the <code>zic</code> man page.
+  </li>
+  <li>
+    The format of <code>zic</code> output files, documented in
+    the <code>tzfile</code> man page.
+  </li>
+  <li>
+    The format of zone table files, documented in <code>zone1970.tab</code>.
+  </li>
+  <li>
+    The format of the country code file, documented in <code>iso3166.tab</code>.
+  </li>
+  <li>
+    The version number of the code and data, as the first line of
+    the text file '<code>version</code>' in each release.
+  </li>
+</ul>
+
+<p>
+Interface changes in a release attempt to preserve compatibility with
+recent releases.
+For example, <code><abbr>tz</abbr></code> data files typically do not
+rely on recently-added <code>zic</code> features, so that users can
+run older <code>zic</code> versions to process newer data files.
+<a href="tz-link.html#download">Downloading
+the <code><abbr>tz</abbr></code> database</a> describes how releases
+are tagged and distributed.
+</p>
+
+<p>
+Interfaces not listed above are less stable.
+For example, users should not rely on particular <abbr>UT</abbr>
+offsets or abbreviations for timestamps, as data entries are often
+based on guesswork and these guesses may be corrected or improved.
+</p>
+</section>
+
+<section>
+  <h2 id="calendar">Calendrical issues</h2>
+<p>
+Calendrical issues are a bit out of scope for a time zone database,
+but they indicate the sort of problems that we would run into if we
+extended the time zone database further into the past.
+An excellent resource in this area is Edward M. Reingold
+and Nachum Dershowitz, <cite><a
+href="https://www.cambridge.org/fr/academic/subjects/computer-science/computing-general-interest/calendrical-calculations-ultimate-edition-4th-edition">Calendrical
+Calculations: The Ultimate Edition</a></cite>, Cambridge University Press (2018).
+Other information and sources are given in the file '<code>calendars</code>'
+in the <code><abbr>tz</abbr></code> distribution.
+They sometimes disagree.
+</p>
+</section>
+
+<section>
+  <h2 id="planets">Time and time zones on other planets</h2>
+<p>
+Some people's work schedules
+use <a href="https://en.wikipedia.org/wiki/Timekeeping on Mars">Mars time</a>.
+Jet Propulsion Laboratory (JPL) coordinators kept Mars time on
+and off during the
+<a href="https://en.wikipedia.org/wiki/Mars_Pathfinder#End_of_mission">Mars
+Pathfinder</a> mission.
+Some of their family members also adapted to Mars time.
+Dozens of special Mars watches were built for JPL workers who kept
+Mars time during the Mars Exploration Rovers mission (2004).
+These timepieces look like normal Seikos and Citizens but use Mars
+seconds rather than terrestrial seconds.
+</p>
+
+<p>
+A Mars solar day is called a "sol" and has a mean period equal to
+about 24 hours 39 minutes 35.244 seconds in terrestrial time.
+It is divided into a conventional 24-hour clock, so each Mars second
+equals about 1.02749125 terrestrial seconds.
+</p>
+
+<p>
+The <a href="https://en.wikipedia.org/wiki/Prime_meridian">prime
+meridian</a> of Mars goes through the center of the crater
+<a href="https://en.wikipedia.org/wiki/Airy-0">Airy-0</a>, named in
+honor of the British astronomer who built the Greenwich telescope that
+defines Earth's prime meridian.
+Mean solar time on the Mars prime meridian is
+called <a href="https://en.wikipedia.org/wiki/Mars_Coordinated_Time">Mars
+Coordinated Time (<abbr>MTC</abbr>)</a>.
+</p>
+
+<p>
+Each landed mission on Mars has adopted a different reference for
+solar time keeping, so there is no real standard for Mars time zones.
+For example, the
+<a href="https://en.wikipedia.org/wiki/Mars_Exploration_Rover">Mars
+Exploration Rover</a> project (2004) defined two time zones "Local
+Solar Time A" and "Local Solar Time B" for its two missions, each zone
+designed so that its time equals local true solar time at
+approximately the middle of the nominal mission.
+Such a "time zone" is not particularly suited for any application
+other than the mission itself.
+</p>
+
+<p>
+Many calendars have been proposed for Mars, but none have achieved
+wide acceptance.
+Astronomers often use Mars Sol Date (<abbr>MSD</abbr>) which is a
+sequential count of Mars solar days elapsed since about 1873-12-29
+12:00 <abbr>GMT</abbr>.
+</p>
+
+<p>
+In our solar system, Mars is the planet with time and calendar most
+like Earth's.
+On other planets, Sun-based time and calendars would work quite
+differently.
+For example, although Mercury's
+<a href="https://en.wikipedia.org/wiki/Rotation_period">sidereal
+rotation period</a> is 58.646 Earth days, Mercury revolves around the
+Sun so rapidly that an observer on Mercury's equator would see a
+sunrise only every 175.97 Earth days, i.e., a Mercury year is 0.5 of a
+Mercury day.
+Venus is more complicated, partly because its rotation is slightly
+<a href="https://en.wikipedia.org/wiki/Retrograde_motion">retrograde</a>:
+its year is 1.92 of its days.
+Gas giants like Jupiter are trickier still, as their polar and
+equatorial regions rotate at different rates, so that the length of a
+day depends on latitude.
+This effect is most pronounced on Neptune, where the day is about 12
+hours at the poles and 18 hours at the equator.
+</p>
+
+<p>
+Although the <code><abbr>tz</abbr></code> database does not support
+time on other planets, it is documented here in the hopes that support
+will be added eventually.
+</p>
+
+<p>
+Sources for time on other planets:
+</p>
+
+<ul>
+  <li>
+    Michael Allison and Robert Schmunk,
+    "<a href="https://www.giss.nasa.gov/tools/mars24/help/notes.html">Technical
+      Notes on Mars Solar Time as Adopted by the Mars24 Sunclock</a>"
+    (2015-06-30).
+  </li>
+  <li>
+    Jia-Rui Chong,
+    "<a href="http://articles.latimes.com/2004/jan/14/science/sci-marstime14">Workdays
+    Fit for a Martian</a>", <cite>Los Angeles Times</cite>
+    (2004-01-14), pp A1, A20&ndash;A21.
+  </li>
+  <li>
+    Tom Chmielewski,
+    "<a href="https://www.theatlantic.com/technology/archive/2015/02/jet-lag-is-worse-on-mars/386033/">Jet
+    Lag Is Worse on Mars</a>", <cite>The Atlantic</cite> (2015-02-26)
+  </li>
+  <li>
+    Matt Williams,
+    "<a href="https://www.universetoday.com/37481/days-of-the-planets/">How
+    long is a day on the other planets of the solar system?</a>"
+    (2017-04-27).
+  </li>
+</ul>
+</section>
+
+<footer>
+  <hr>
+  This file is in the public domain, so clarified as of 2009-05-17 by
+  Arthur David Olson.
+</footer>
+</body>
+</html>
diff --git a/time2posix.3 b/time2posix.3
new file mode 100644
index 000000000000..e4b8e8199063
--- /dev/null
+++ b/time2posix.3
@@ -0,0 +1,129 @@
+.TH TIME2POSIX 3
+.SH NAME
+time2posix, posix2time \- convert seconds since the Epoch
+.SH SYNOPSIS
+.nf
+.ie \n(.g .ds - \f(CW-\fP
+.el ds - \-
+.B #include <time.h>
+.PP
+.B time_t time2posix(time_t t);
+.PP
+.B time_t posix2time(time_t t);
+.PP
+.B cc ... \*-ltz
+.fi
+.SH DESCRIPTION
+.ie '\(en'' .ds en \-
+.el .ds en \(en
+.ie '\(lq'' .ds lq \&"\"
+.el .ds lq \(lq\"
+.ie '\(rq'' .ds rq \&"\"
+.el .ds rq \(rq\"
+.de q
+\\$3\*(lq\\$1\*(rq\\$2
+..
+IEEE Standard 1003.1
+(POSIX)
+requires the time_t value 536457599 to stand for 1986-12-31 23:59:59 UTC.
+This effectively implies that POSIX time_t values cannot include leap
+seconds and,
+therefore,
+that the system time must be adjusted as each leap occurs.
+.PP
+If the time package is configured with leap-second support
+enabled,
+however,
+no such adjustment is needed and
+time_t values continue to increase over leap events
+(as a true
+.q "seconds since..."
+value).
+This means that these values will differ from those required by POSIX
+by the net number of leap seconds inserted since the Epoch.
+.PP
+Typically this is not a problem as the type time_t is intended
+to be
+(mostly)
+opaque \*(en time_t values should only be obtained-from and
+passed-to functions such as
+.IR time(2) ,
+.IR localtime(3) ,
+.IR mktime(3) ,
+and
+.IR difftime(3) .
+However,
+POSIX gives an arithmetic
+expression for directly computing a time_t value from a given date/time,
+and the same relationship is assumed by some
+(usually older)
+applications.
+Any programs creating/dissecting time_t's
+using such a relationship will typically not handle intervals
+over leap seconds correctly.
+.PP
+The
+.I time2posix
+and
+.I posix2time
+functions are provided to address this time_t mismatch by converting
+between local time_t values and their POSIX equivalents.
+This is done by accounting for the number of time-base changes that
+would have taken place on a POSIX system as leap seconds were inserted
+or deleted.
+These converted values can then be used in lieu of correcting the older
+applications,
+or when communicating with POSIX-compliant systems.
+.PP
+.I Time2posix
+is single-valued.
+That is,
+every local time_t
+corresponds to a single POSIX time_t.
+.I Posix2time
+is less well-behaved:
+for a positive leap second hit the result is not unique,
+and for a negative leap second hit the corresponding
+POSIX time_t doesn't exist so an adjacent value is returned.
+Both of these are good indicators of the inferiority of the
+POSIX representation.
+.PP
+The following table summarizes the relationship between a time
+T and it's conversion to,
+and back from,
+the POSIX representation over the leap second inserted at the end of June,
+1993.
+.nf
+.ta \w'93/06/30 'u +\w'23:59:59 'u +\w'A+0 'u +\w'X=time2posix(T) 'u
+DATE	TIME	T	X=time2posix(T)	posix2time(X)
+93/06/30	23:59:59	A+0	B+0	A+0
+93/06/30	23:59:60	A+1	B+1	A+1 or A+2
+93/07/01	00:00:00	A+2	B+1	A+1 or A+2
+93/07/01	00:00:01	A+3	B+2	A+3
+
+A leap second deletion would look like...
+
+DATE	TIME	T	X=time2posix(T)	posix2time(X)
+??/06/30	23:59:58	A+0	B+0	A+0
+??/07/01	00:00:00	A+1	B+2	A+1
+??/07/01	00:00:01	A+2	B+3	A+2
+.sp
+.ce
+	[Note: posix2time(B+1) => A+0 or A+1]
+.fi
+.PP
+If leap-second support is not enabled,
+local time_t's and
+POSIX time_t's are equivalent,
+and both
+.I time2posix
+and
+.I posix2time
+degenerate to the identity function.
+.SH SEE ALSO
+difftime(3),
+localtime(3),
+mktime(3),
+time(2)
+.\" This file is in the public domain, so clarified as of
+.\" 1996-06-05 by Arthur David Olson.
diff --git a/time2posix.3.txt b/time2posix.3.txt
new file mode 100644
index 000000000000..d9db97010ebe
--- /dev/null
+++ b/time2posix.3.txt
@@ -0,0 +1,76 @@
+TIME2POSIX(3)              Library Functions Manual              TIME2POSIX(3)
+
+NAME
+       time2posix, posix2time - convert seconds since the Epoch
+
+SYNOPSIS
+       #include <time.h>
+
+       time_t time2posix(time_t t);
+
+       time_t posix2time(time_t t);
+
+       cc ... -ltz
+
+DESCRIPTION
+       IEEE Standard 1003.1 (POSIX) requires the time_t value 536457599 to
+       stand for 1986-12-31 23:59:59 UTC.  This effectively implies that POSIX
+       time_t values cannot include leap seconds and, therefore, that the
+       system time must be adjusted as each leap occurs.
+
+       If the time package is configured with leap-second support enabled,
+       however, no such adjustment is needed and time_t values continue to
+       increase over leap events (as a true "seconds since..."  value).  This
+       means that these values will differ from those required by POSIX by the
+       net number of leap seconds inserted since the Epoch.
+
+       Typically this is not a problem as the type time_t is intended to be
+       (mostly) opaque - time_t values should only be obtained-from and
+       passed-to functions such as time(2), localtime(3), mktime(3), and
+       difftime(3).  However, POSIX gives an arithmetic expression for
+       directly computing a time_t value from a given date/time, and the same
+       relationship is assumed by some (usually older) applications.  Any
+       programs creating/dissecting time_t's using such a relationship will
+       typically not handle intervals over leap seconds correctly.
+
+       The time2posix and posix2time functions are provided to address this
+       time_t mismatch by converting between local time_t values and their
+       POSIX equivalents.  This is done by accounting for the number of time-
+       base changes that would have taken place on a POSIX system as leap
+       seconds were inserted or deleted.  These converted values can then be
+       used in lieu of correcting the older applications, or when
+       communicating with POSIX-compliant systems.
+
+       Time2posix is single-valued.  That is, every local time_t corresponds
+       to a single POSIX time_t.  Posix2time is less well-behaved: for a
+       positive leap second hit the result is not unique, and for a negative
+       leap second hit the corresponding POSIX time_t doesn't exist so an
+       adjacent value is returned.  Both of these are good indicators of the
+       inferiority of the POSIX representation.
+
+       The following table summarizes the relationship between a time T and
+       it's conversion to, and back from, the POSIX representation over the
+       leap second inserted at the end of June, 1993.
+       DATE     TIME     T   X=time2posix(T) posix2time(X)
+       93/06/30 23:59:59 A+0 B+0             A+0
+       93/06/30 23:59:60 A+1 B+1             A+1 or A+2
+       93/07/01 00:00:00 A+2 B+1             A+1 or A+2
+       93/07/01 00:00:01 A+3 B+2             A+3
+
+       A leap second deletion would look like...
+
+       DATE     TIME     T   X=time2posix(T) posix2time(X)
+       ??/06/30 23:59:58 A+0 B+0             A+0
+       ??/07/01 00:00:00 A+1 B+2             A+1
+       ??/07/01 00:00:01 A+2 B+3             A+2
+
+                            [Note: posix2time(B+1) => A+0 or A+1]
+
+       If leap-second support is not enabled, local time_t's and POSIX
+       time_t's are equivalent, and both time2posix and posix2time degenerate
+       to the identity function.
+
+SEE ALSO
+       difftime(3), localtime(3), mktime(3), time(2)
+
+                                                                 TIME2POSIX(3)
diff --git a/tz-art.html b/tz-art.html
new file mode 100644
index 000000000000..9624d8cd2292
--- /dev/null
+++ b/tz-art.html
@@ -0,0 +1,610 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+<meta charset="UTF-8">
+<title>Time and the Arts</title>
+</head>
+<body>
+<h1>Time and the Arts</h1>
+<h2>Documentaries</h2>
+<ul>
+<li>
+"<a href="https://www.youtube.com/watch?v=84aWtseb2-4">Daylight
+Saving Time Explained</a>" (2011; 6:39) lightly covers daylight saving
+time's theory, history, pros and cons. Among other things, it explains
+Arizona's daylight-saving enclaves quite well.</li>
+<li>
+"<a href="https://www.youtube.com/watch?v=-5wpm-gesOY">The Problem
+with Time &amp; Timezones &ndash; Computerphile</a>" (2013; 10:12) delves
+into problems that programmers have with timekeeping.</li>
+<li>
+<a href="https://www.rferl.org/a/28375932.html">All The Time In The World:
+Explaining The Mysteries Of Time Zones</a>" (2017; 2:15)
+briefly says why France has more time zones than Russia.
+<li>
+"About Time" (1962; 53 minutes) is part of the
+Bell Science extravaganza, with Frank Baxter, Richard Deacon, and Les Tremayne.
+Its advisor was Richard Feynman, and it was voiced by Mel Blanc.
+(<a href="http://www.imdb.com/title/tt0154110/">IMDb entry</a>.)</li>
+</ul>
+<h2>Movies</h2>
+<ul>
+<li>
+In the 1946 movie <em>A Matter of Life and Death</em>
+(U.S. title <em>Stairway to Heaven</em>)
+there is a reference to British Double Summer Time.
+The time does not play a large part in the plot;
+it's just a passing reference to the time when one of the
+characters was supposed to have died (but didn't).
+The IMDb page is at
+<a href="http://us.imdb.com/title/tt0038733/">
+http://us.imdb.com/title/tt0038733/
+</a>. (Dave Cantor)
+<li>
+The 1953 railway comedy movie <em>The Titfield Thunderbolt</em> includes a
+play on words on British Double Summer Time. Valentine's wife wants
+him to leave the pub and asks him, "Do you know what time it is?"
+And he, happy where he is, replies: "Yes, my love. Summer double time."
+IMDb page:
+<a href="http://us.imdb.com/title/tt0046436/">
+http://us.imdb.com/title/tt0046436/
+</a>. (Mark Brader, 2009-10-02)
+</li>
+<li>
+The premise of the 1999 caper movie <em>Entrapment</em> involves computers
+in an international banking network being shut down briefly at
+midnight in each time zone to avoid any problems at the transition
+from the year 1999 to 2000 in that zone. (Hmmmm.) If this shutdown
+is extended by 10 seconds, it will create a one-time opportunity for
+a gigantic computerized theft. To achieve this, at one location the
+crooks interfere with the microwave system supplying time signals to
+the computer, advancing the time by 0.1 second each minute over the
+last hour of 1999. (So this movie teaches us that 0.1 &times; 60 = 10.)
+IMDb page:
+<a href="http://us.imdb.com/title/tt0137494/">
+http://us.imdb.com/title/tt0137494/
+</a>. (Mark Brader, 2009-10-02)
+</li>
+<li>
+One mustn't forget the
+<a href="https://www.youtube.com/watch?v=k4EUTMPuvHo">trailer</a>
+(2014; 2:23) for the movie <em>Daylight Saving</em>.
+</li>
+</ul>
+<h2>TV episodes</h2>
+<ul>
+<li>
+An episode of <em>The Adventures of Superman</em> entitled "The Mysterious
+Cube," first aired 1958-02-24, had Superman convincing the controllers
+of the Arlington Time Signal to broadcast ahead of actual time;
+doing so got a crook trying to be declared dead to
+emerge a bit too early from the titular enclosure.
+</li>
+<li>
+"The Chimes of Big Ben", <em>The Prisoner</em>, episode 2, ITC, 1967-10-06.
+Our protagonist tumbles to
+the fraudulent nature of a Poland-to-England escape upon hearing "Big
+Ben" chiming on Polish local time.
+</li>
+<li>
+"The Susie", <em>Seinfeld</em>, season 8, episode 15, NBC, 1997-02-13.
+Kramer decides that daylight saving time
+isn't coming fast enough, so he sets his watch ahead an hour.
+</li>
+<li>
+"20 Hours in America", <em>The West Wing</em>, season 4, episodes 1&ndash;2,
+2002-09-25, contained a <a
+href="https://www.youtube.com/watch?v=-J1NHzQ1sgc">scene</a> that
+saw White House staffers stranded in Indiana; they thought they had time to
+catch Air Force One but were done in by intra-Indiana local time changes.
+</li>
+<li>
+"In what time zone would you find New York City?" was a $200 question on
+the 1999-11-13 United States airing of <em>Who Wants to Be a Millionaire?</em>,
+and "In 1883, what industry led the movement to divide the U.S. into four time
+zones?" was a $32,000 question on the 2001-05-23 United States airing of
+the same show. At this rate, the million-dollar time-zone
+question should have been asked 2002-06-04.
+</li>
+<li>
+A private jet's mid-flight change of time zones distorts Alison Dubois'
+premonition in the "We Had a Dream" episode of <em>Medium</em>
+(originally aired 2007-02-28).
+</li>
+<li>
+In the <em>30 Rock</em> episode "Anna Howard Shaw Day"
+(first broadcast 2010-02-11),
+Jack Donaghy's date realizes that a Geneva-to-New-York business phone call
+received in the evening must be fake given the difference in local times.
+</li>
+<li>
+In the "Run by the Monkeys" episode of <em>Da Vinci's Inquest</em>
+(first broadcast 2002-11-17),
+a witness in a five-year-old fire case realizes they may not have set
+their clock back when daylight saving ended on the day of the fire,
+introducing the possibility of an hour when arson might have occurred.
+</li>
+<li>
+In "The Todd Couple" episode of <em>Outsourced</em> (first aired 2011-02-10),
+Manmeet sets up Valentine's Day teledates for 6:00 and 9:00pm;
+since one is with a New Yorker and the other with a San Franciscan,
+hilarity ensues.
+(Never mind that this should be 7:30am in Mumbai, yet for some reason the show
+proceeds as though it's also mid-evening there.)
+</li>
+<li>
+In the "14 Days to Go"/"T Minus..." episode of
+<em>You, Me and the Apocalypse</em>
+(first aired 2015-11-11 in the UK, 2016-03-10 in the US),
+the success of a mission to deal with a comet
+hinges on whether or not Russia observes daylight saving time.
+(In the US, the episode first aired in the week before the switch to DST.)
+</li>
+<li>
+"The Lost Hour", <em>Eerie, Indiana</em>, episode 10, NBC, 1991-12-01.
+Despite Indiana's then-lack of DST, Marshall changes his clock with
+unusual consequences.
+See "<a
+href="https://www.avclub.com/eerie-indiana-was-a-few-dimensions-ahead-of-its-time-1819833380"><em>Eerie,
+Indiana</em> was a few dimensions ahead of its time</a>".
+</li>
+<li>
+"Time Tunnel", <em>The Adventures of Pete &amp; Pete</em>, season 2, episode 5,
+Nickelodeon, 1994-10-23.
+The two Petes travel back in time an hour on the day that DST ends.
+</li>
+<li>
+"King-Size Homer", <em>The Simpsons</em>, episode 135, Fox, 1995-11-05.
+Homer, working from home, remarks "8:58, first
+time I've ever been early for work. Except for all those daylight
+savings days. Lousy farmers."
+</li>
+<li>
+"Tracks", <em>The Good Wife</em>, season 7, episode 12,
+CBS, 2016-01-17.
+The applicability of a contract hinges on the
+time zone associated with a video timestamp.
+</li>
+<li>
+"Justice", <em>Veep</em>, season 6, episode 4, HBO, 2017-05-07.
+Jonah's inability to understand DST ends up impressing a wealthy
+backer who sets him up for a 2020 presidential run.
+</li>
+</ul>
+<h2>Books, plays, and magazines</h2>
+<ul>
+<li>
+Jules Verne, <em>Around the World in Eighty Days</em>
+(<em>Le tour du monde en quatre-vingts jours</em>), 1873.
+Wall-clock time plays a central role in the plot.
+European readers of the 1870s clearly held the U.S. press in
+deep contempt; the protagonists cross the U.S. without once
+reading a paper.
+Available versions include
+<a href="http://www.literature.org/Works/Jules-Verne/eighty">an English
+translation</a>, and
+<a href="https://fourmilab.ch/etexts/www/tdm80j">the original French</a>
+"with illustrations from the original 1873 French-language edition".
+</li>
+<li>
+Nick Enright, <em>Daylight Saving</em>, 1989.
+A fast-paced comedy about love and loneliness as the clocks turn back.
+</li>
+<li>
+Umberto Eco, <em>The Island of the Day Before</em>
+(<em>L'isola del giorno prima</em>), 1994.
+"...the story of a 17th century Italian nobleman trapped near an island
+on the International Date Line.  Time and time zones play an integral
+part in the novel." (Paul Eggert, 2006-04-22)
+</li>
+<li>
+John Dunning, <a
+href="http://books.simonandschuster.com/Two-OClock-Eastern-Wartime/John-Dunning/9781439171530"><em>Two
+O'Clock, Eastern Wartime</em></a>, 2001.
+Mystery, history, daylight saving time, and old-time radio.
+</li>
+<li>
+Surrealist artist Guy Billout's work "Date Line" appeared on page 103
+of the 1999-11 <em>Atlantic Monthly</em>.
+</li>
+<li>
+"Gloom, Gloom, Go Away" by Walter Kirn appeared on page 106 of <em>Time</em>
+magazine's 2002-11-11 issue; among other things, it proposed
+year-round DST as a way of lessening wintertime despair.
+</li>
+</ul>
+<h2>Music</h2>
+<p>
+Data on recordings of "Save That Time," Russ Long, Serrob Publishing, BMI:</p>
+<table>
+<tr><td>Artist</td><td>Karrin Allyson</td></tr>
+<tr><td>CD</td><td>I Didn't Know About You</td></tr>
+<tr><td>Copyright Date</td><td>1993</td></tr>
+<tr><td>Label</td><td>Concord Jazz, Inc.</td></tr>
+<tr><td>ID</td><td>CCD-4543</td></tr>
+<tr><td>Track Time</td><td>3:44</td></tr>
+<tr><td>Personnel</td><td>Karrin Allyson, vocal;
+Russ Long, piano;
+Gerald Spaits, bass;
+Todd Strait, drums</td></tr>
+<tr><td>Notes</td><td>CD notes "additional lyric by Karrin Allyson;
+arranged by Russ Long and Karrin Allyson"</td></tr>
+<tr><td>ADO Rating</td><td>1 star</td></tr>
+<tr><td><a href="http://www.allmusic.com/album/i-didnt-know-about-you-mw0000618657">AMG Rating</a></td><td>4 stars</td></tr>
+<tr><td>Penguin Rating</td><td>3.5 stars</td></tr>
+<tr><td>&nbsp;</td><td></td></tr>
+<tr><td>Artist</td><td>Kevin Mahogany</td></tr>
+<tr><td>CD</td><td>Double Rainbow</td></tr>
+<tr><td>Copyright Date</td><td>1993</td></tr>
+<tr><td>Label</td><td>Enja Records</td></tr>
+<tr><td>ID</td><td>ENJ-7097 2</td></tr>
+<tr><td>Track Time</td><td>6:27</td></tr>
+<tr><td>Personnel</td><td>Kevin Mahogany, vocal;
+Kenny Barron, piano;
+Ray Drummond, bass;
+Ralph Moore, tenor saxophone;
+Lewis Nash, drums</td></tr>
+<tr><td>ADO Rating</td><td>1.5 stars</td></tr>
+<tr><td><a href="http://www.allmusic.com/album/double-rainbow-mw0000620371">AMG Rating</a></td><td>3 stars</td></tr>
+<tr><td>Penguin Rating</td><td>3 stars</td></tr>
+<tr><td>&nbsp;</td><td></td></tr>
+<tr><td>Artist</td><td>Joe Williams</td></tr>
+<tr><td>CD</td><td>Here's to Life</td></tr>
+<tr><td>Copyright Date</td><td>1994</td></tr>
+<tr><td>Label</td><td>Telarc International Corporation</td></tr>
+<tr><td>ID</td><td>CD-83357</td></tr>
+<tr><td>Track Time</td><td>3:58</td></tr>
+<tr><td>Personnel</td><td>Joe Williams, vocal
+The Robert Farnon [39 piece] Orchestra</td></tr>
+<tr><td>Notes</td><td>This CD is also available as part of a 3-CD package from
+Telarc, "Triple Play" (CD-83461)</td></tr>
+<tr><td>ADO Rating</td><td>black dot</td></tr>
+<tr><td><a href="http://www.allmusic.com/album/heres-to-life-mw0000623648">AMG Rating</a></td><td>2 stars</td></tr>
+<tr><td>Penguin Rating</td><td>3 stars</td></tr>
+<tr><td>&nbsp;</td><td></td></tr>
+<tr><td>Artist</td><td>Charles Fambrough</td></tr>
+<tr><td>CD</td><td>Keeper of the Spirit</td></tr>
+<tr><td>Copyright Date</td><td>1995</td></tr>
+<tr><td>Label</td><td>AudioQuest Music</td></tr>
+<tr><td>ID</td><td>AQ-CD1033</td></tr>
+<tr><td>Track Time</td><td>7:07</td></tr>
+<tr><td>Personnel</td><td>Charles Fambrough, bass;
+Joel Levine, tenor recorder;
+Edward Simon, piano;
+Lenny White, drums;
+Marion Simon, percussion</td></tr>
+<tr><td>ADO Rating</td><td>2 stars</td></tr>
+<tr><td><a href="http://www.allmusic.com/album/keeper-of-the-spirit-mw0000176559">AMG Rating</a></td><td>unrated</td></tr>
+<tr><td>Penguin Rating</td><td>3 stars</td></tr>
+</table>
+<hr>
+<p>Also of note:</p>
+<table>
+<tr><td>Artist</td><td>Holly Cole Trio</td></tr>
+<tr><td>CD</td><td>Blame It On My Youth</td></tr>
+<tr><td>Copyright Date</td><td>1992</td></tr>
+<tr><td>Label</td><td>Manhattan</td></tr>
+<tr><td>ID</td><td>CDP 7 97349 2</td></tr>
+<tr><td>Total Time</td><td>37:45</td></tr>
+<tr><td>Personnel</td><td>Holly Cole, voice;
+Aaron Davis, piano;
+David Piltch, string bass</td></tr>
+<tr><td>Notes</td><td>Lyrical reference to "Eastern Standard Time" in
+Tom Waits' "Purple Avenue"</td></tr>
+<tr><td>ADO Rating</td><td>2.5 stars</td></tr>
+<tr><td><a href="http://www.allmusic.com/album/blame-it-on-my-youth-mw0000274303">AMG Rating</a></td><td>3 stars</td></tr>
+<tr><td>Penguin Rating</td><td>unrated</td></tr>
+<tr><td>&nbsp;</td><td></td></tr>
+<tr><td>Artist</td><td>Milt Hinton</td></tr>
+<tr><td>CD</td><td>Old Man Time</td></tr>
+<tr><td>Copyright Date</td><td>1990</td></tr>
+<tr><td>Label</td><td>Chiaroscuro</td></tr>
+<tr><td>ID</td><td>CR(D) 310</td></tr>
+<tr><td>Total Time</td><td>149:38 (two CDs)</td></tr>
+<tr><td>Personnel</td><td>Milt Hinton, bass;
+Doc Cheatham, Dizzy Gillespie, Clark Terry, trumpet;
+Al Grey, trombone;
+Eddie Barefield, Joe Camel (Flip Phillips), Buddy Tate,
+clarinet and saxophone;
+John Bunch, Red Richards, Norman Simmons, Derek Smith,
+Ralph Sutton, piano;
+Danny Barker, Al Casey, guitar;
+Gus Johnson, Gerryck King, Bob Rosengarden, Jackie Williams,
+drums;
+Lionel Hampton, vibraphone;
+Cab Calloway, Joe Williams, vocal;
+Buck Clayton, arrangements</td></tr>
+<tr><td>Notes</td><td>tunes include Old Man Time, Time After Time,
+Sometimes I'm Happy,
+A Hot Time in the Old Town Tonight,
+Four or Five Times, Now's the Time,
+Time on My Hands, This Time It's Us,
+and Good Time Charlie.
+<a href="http://www.chiaroscurojazz.com/album.php?C=310">Album info</a>
+is available.</td></tr>
+<tr><td>ADO Rating</td><td>3 stars</td></tr>
+<tr><td><a href="http://www.allmusic.com/album/old-man-time-mw0000269353">AMG Rating</a></td><td>4.5 stars</td></tr>
+<tr><td>Penguin Rating</td><td>3 stars</td></tr>
+<tr><td>&nbsp;</td><td></td></tr>
+<tr><td>Artist</td><td>Alan Broadbent</td></tr>
+<tr><td>CD</td><td>Pacific Standard Time</td></tr>
+<tr><td>Copyright Date</td><td>1995</td></tr>
+<tr><td>Label</td><td>Concord Jazz, Inc.</td></tr>
+<tr><td>ID</td><td>CCD-4664</td></tr>
+<tr><td>Total Time</td><td>62:42</td></tr>
+<tr><td>Personnel</td><td>Alan Broadbent, piano;
+Putter Smith, Bass;
+Frank Gibson, Jr., drums</td></tr>
+<tr><td>Notes</td><td>The CD cover features an analemma for equation-of-time fans</td></tr>
+<tr><td>ADO Rating</td><td>1 star</td></tr>
+<tr><td><a href="http://www.allmusic.com/album/pacific-standard-time-mw0000645433">AMG Rating</a></td><td>4 stars</td></tr>
+<tr><td>Penguin Rating</td><td>3.5 stars</td></tr>
+<tr><td>&nbsp;</td><td></td></tr>
+<tr><td>Artist</td><td>Anthony Braxton/Richard Teitelbaum</td></tr>
+<tr><td>CD</td><td>Silence/Time Zones</td></tr>
+<tr><td>Copyright Date</td><td>1996</td></tr>
+<tr><td>Label</td><td>Black Lion</td></tr>
+<tr><td>ID</td><td>BLCD 760221</td></tr>
+<tr><td>Total Time</td><td>72:58</td></tr>
+<tr><td>Personnel</td><td>Anthony Braxton, sopranino and alto saxophones,
+contrebasse clarinet, miscellaneous instruments;
+Leo Smith, trumpet and miscellaneous instruments;
+Leroy Jenkins, violin and miscellaneous instruments;
+Richard Teitelbaum, modular moog and micromoog synthesizer</td></tr>
+<tr><td>ADO Rating</td><td>black dot</td></tr>
+<tr><td><a href="http://www.allmusic.com/album/silence-time-zones-mw0000595735">AMG Rating</a></td><td>4 stars</td></tr>
+<tr><td>&nbsp;</td><td></td></tr>
+<tr><td>Artist</td><td>Charles Gayle</td></tr>
+<tr><td>CD</td><td>Time Zones</td></tr>
+<tr><td>Copyright Date</td><td>2006</td></tr>
+<tr><td>Label</td><td>Tompkins Square</td></tr>
+<tr><td>ID</td><td>TSQ2839</td></tr>
+<tr><td>Total Time</td><td>49:06</td></tr>
+<tr><td>Personnel</td><td>Charles Gayle, piano</td></tr>
+<tr><td>ADO Rating</td><td>1 star</td></tr>
+<tr><td><a href="http://www.allmusic.com/album/time-zones-mw0000349642">AMG Rating</a></td><td>4.5 stars</td></tr>
+<tr><td>&nbsp;</td><td></td></tr>
+<tr><td>Artist</td><td>The Get Up Kids</td></tr>
+<tr><td>CD</td><td>Eudora</td></tr>
+<tr><td>Copyright Date</td><td>2001</td></tr>
+<tr><td>Label</td><td>Vagrant</td></tr>
+<tr><td>ID</td><td>357</td></tr>
+<tr><td>Total Time</td><td>65:12</td></tr>
+<tr><td>Notes</td><td>Includes the song "Central Standard Time." Thanks to Colin Bowern for this information.</td></tr>
+<tr><td><a href="http://www.allmusic.com/album/eudora-mw0000592063">AMG Rating</a></td><td>2.5 stars</td></tr>
+<tr><td>&nbsp;</td><td></td></tr>
+
+<tr><td>Artist</td><td>Coldplay</td></tr>
+<tr><td>Song</td><td>Clocks</td></tr>
+<tr><td>Copyright Date</td><td>2003</td></tr>
+<tr><td>Label</td><td>Capitol Records</td></tr>
+<tr><td>ID</td><td>52608</td></tr>
+<tr><td>Total Time</td><td>4:13</td></tr>
+<tr><td>Notes</td><td>Won the 2004 Record of the Year honor at the
+Grammy Awards. Co-written and performed by Chris Martin,
+great-great-grandson of DST inventor William Willett. The song's first
+line is "Lights go out and I can't be saved".</td></tr>
+<tr><td>&nbsp;</td><td></td></tr>
+
+<tr><td>Artist</td><td>Jaime Guevara</td></tr>
+<tr><td>Song</td><td><a
+href="https://www.youtube.com/watch?v=ZfN4Fe_A50U">Qu&eacute;
+hora es</a></td></tr>
+<tr><td>Date</td><td>1993</td></tr>
+<tr><td>Total Time</td><td>3:04</td></tr>
+<tr><td>Notes</td><td>The song protested "Sixto Hour" in Ecuador
+(1992&ndash;3). Its lyrics include "Amanec&iacute;a en mitad de la noche, los
+guaguas iban a clase sin sol" ("It was dawning in the middle of the
+night, the buses went to class without sun").
+<tr><td>&nbsp;</td><td></td></tr>
+
+<tr><td>Artist</td><td>Irving Kahal and Harry Richman</td></tr>
+<tr><td>Song</td><td>There Ought to be a Moonlight Saving Time</td></tr>
+<tr><td>Copyright Date</td><td>1931</td>
+<tr><td>Notes</td><td>This musical standard was a No. 1 hit for Guy Lombardo
+in 1931, and was also performed by Maurice Chevalier, Blossom Dearie
+and many others. The phrase "Moonlight saving time" also appears in
+the 1995 country song "Not Enough Hours in the Night" written by Aaron
+Barker, Kim Williams and Rob Harbin and performed by Doug
+Supernaw.</td></tr>
+<tr><td>&nbsp;</td><td></td></tr>
+
+<tr><td>Artist</td><td>The Microscopic Septet</td></tr>
+<tr><td>CD</td><td>Lobster Leaps In</td></tr>
+<tr><td>Copyright Date</td><td>2008</td></tr>
+<tr><td>Label</td><td>Cuneiform</td></tr>
+<tr><td>ID</td><td>272</td></tr>
+<tr><td>Total Time</td><td>73:05</td></tr>
+<tr><td>Notes</td><td>Includes the song "Twilight Time Zone."</td></tr>
+<tr><td><a href="http://www.allmusic.com/album/lobster-leaps-in-mw0000794929">AMG Rating</a></td><td>3.5 stars</td></tr>
+<tr><td>ADO Rating</td><td>2 stars</td></tr>
+
+<tr><td>&nbsp;</td><td></td></tr>
+
+<tr><td>Artist</td><td>Bob Dylan</td></tr>
+<tr><td>CD</td><td>The Times They Are a-Changin'</td></tr>
+<tr><td>Copyright Date</td><td>1964</td></tr>
+<tr><td>Label</td><td>Columbia</td></tr>
+<tr><td>ID</td><td>CK-8905</td></tr>
+<tr><td>Total Time</td><td>45:36</td></tr>
+<tr><td><a href="http://www.allmusic.com/album/the-times-they-a-changin-mw0000202344">AMG Rating</a></td><td>4.5 stars</td></tr>
+<tr><td>ADO Rating</td><td>1.5 stars</td></tr>
+<tr><td>Notes<td>The title song is also available on "Bob Dylan's Greatest Hits" and "The Essential Bob Dylan."</td></tr>
+<tr><td>&nbsp;</td><td></td></tr>
+
+<tr><td>Artist</td><td>Luciana Souza</td></tr>
+<tr><td>CD</td><td>Tide</td></tr>
+<tr><td>Copyright Date</td><td>2009</td></tr>
+<tr><td>Label</td><td>Universal Jazz France</td></tr>
+<tr><td>ID</td><td>B0012688-02</td></tr>
+<tr><td>Total Time</td><td>42:31</td></tr>
+<tr><td><a href="http://www.allmusic.com/album/tide-mw0000815692">AMG Rating</a></td><td>3.5 stars</td></tr>
+<tr><td>ADO Rating</td><td>2.5 stars</td></tr>
+<tr><td>Notes<td>Includes the song "Fire and Wood" with the lyric
+"The clocks were turned back you remember/Think it's still November."
+</td></tr>
+<tr><td>&nbsp;</td><td></td></tr>
+<tr><td>Artist</td><td>Ken Nordine</td></tr>
+<tr><td>CD</td><td>You're Getting Better: The Word Jazz Dot Masters</td></tr>
+<tr><td>Copyright Date</td><td>2005</td></tr>
+<tr><td>Label</td><td>Geffen</td></tr>
+<tr><td>ID</td><td>B0005171-02</td></tr>
+<tr><td>Total Time</td><td>156:22</td></tr>
+<tr><td>ADO Rating</td><td>1 star</td></tr>
+<tr><td><a href="http://www.allmusic.com/album/youre-getting-better-the-word-jazz-dot-masters-mw0000736197">AMG Rating</a></td><td>4.5 stars</td></tr>
+<tr><td>Notes</td><td>Includes the piece "What Time Is It"
+("He knew what time it was everywhere...that counted").</td></tr>
+</table>
+<h2>Comics</h2>
+<ul>
+<li>
+The webcomic <em>xkcd</em> has the strip
+"<a href='https://xkcd.com/673/'>The Sun</a>" (2009-12-09) and the panels
+"<a href='https://xkcd.com/1017/'>Backward in Time</a>" (2012-02-14),
+"<a href='https://xkcd.com/1061/'>EST</a>" (2012-05-28),
+"<a href='https://xkcd.com/1179/'>ISO 8601</a>" (2013-02-27),
+"<a href='https://xkcd.com/1335/'>Now</a>" (2014-02-26),
+"<a href='https://xkcd.com/1655/'>Doomsday Clock</a>" (2016-03-14),
+"<a href='https://xkcd.com/1799/'>Bad Map Projection: Time Zones</a>"
+(2017-02-15), and
+"<a href='https://xkcd.com/1883/'>Supervillain Plan</a>" (2017-08-30).
+The related book <em>What If?</em> has an entry
+"<a href='https://what-if.xkcd.com/26/'>Leap Seconds</a>" (2012-12-31).
+</li>
+<li>
+Pig kills time in <a
+href="http://www.gocomics.com/pearlsbeforeswine/2016/11/06"><em>Pearls
+Before Swine</em> (2016-11-06)</a>.
+</li>
+<li>
+Stonehenge is abandoned in <a
+href='http://www.gocomics.com/nonsequitur/2017/03/12'><em>Non Sequitur</em>
+(2017-03-12)</a>.
+<li>
+The boss freaks out in <a
+href='http://dilbert.com/strip/1998-03-14'><em>Dilbert</em> (1998-03-14)</a>.
+</li>
+<li>
+Peppermint Patty: "What if the world comes to an end tonight, Marcie?"
+<br>
+Marcie: "I promise there'll be a tomorrow, sir ... in fact,
+it's already tomorrow in Australia!"
+<br>
+(Charles M. Schulz, <a href='http://www.gocomics.com/peanuts/1980/06/13'><em>Peanuts</em>, 1980-06-13</a>)
+</li>
+</ul>
+<h2>Jokes</h2>
+<ul>
+<li>
+The idea behind daylight saving time was first proposed as a joke by
+Benjamin Franklin. To enforce it, he suggested, "Every
+morning, as soon as the sun rises, let all the bells in every church
+be set ringing; and if that is not sufficient, let cannon be fired in
+every street, to wake the sluggards effectually, and make them open
+their eyes to see their true interest. All the difficulty will be in
+the first two or three days: after which the reformation will be as
+natural and easy as the present irregularity; for, <em>ce n'est que le
+premier pas qui co&ucirc;te</em>."
+<a href="http://www.webexhibits.org/daylightsaving/franklin3.html">Franklin's
+joke</a> was first published on 1784-04-26 by the
+<em>Journal de Paris</em> as <a
+href="https://en.wikipedia.org/wiki/File:Franklin-Benjamin-Journal-de-Paris-1784.jpg">an
+anonymous letter translated into French</a>.
+</li>
+<li>
+"We've been using the five-cent nickel in this country since 1492.
+Now that's pretty near 100 years, daylight saving."
+(Groucho Marx as Captain Spaulding in <em>Animal Crackers</em>, 1930,
+as noted by Will Fitzgerald)
+</li>
+<li>
+BRADY. ...[Bishop Usher] determined that the Lord began the Creation
+on the 23rd of October in the Year 4,004 B.C. at &ndash; uh, 9 A.M.!
+<br>
+DRUMMOND. That Eastern Standard Time? (<em>Laughter.</em>) Or Rocky Mountain
+Time? (<em>More laughter.</em>) It wasn't daylight-saving time, was it? Because
+the Lord didn't make the sun until the fourth day!
+<br>
+(From the play <em>Inherit the Wind</em> by Jerome Lawrence and Robert E. Lee,
+filmed in 1960 with Spencer Tracy as Drummond and Fredric March as
+Brady, and several other times. Thanks to Mark Brader.)
+</li>
+<li>
+"Good news."
+"What did they do? Extend Daylight Saving Time year round?"
+(Professional tanner George Hamilton, in dialog from a
+May, 1999 episode of the syndicated television series <em>Baywatch</em>)
+</li>
+<li>
+"A fundamental belief held by Americans is that if you are on land, you
+cannot be killed by a fish...So most Americans remain on land, believing
+they're safe. Unfortunately, this belief &ndash; like so many myths, such as that
+there's a reason for 'Daylight Saving Time' &ndash; is false."
+(Dave Barry column, 2000-07-02)
+</li>
+<li>
+"I once had sex for an hour and five minutes, but that was on the day
+when you turn the clocks ahead."
+(Garry Shandling, 52nd Annual Emmys, 2000-09-10)
+</li>
+<li>
+"Would it impress you if I told you I invented Daylight Savings Time?"
+("Sahjhan" to "Lilah" in dialog from the "Loyalty" episode of <em>Angel</em>,
+originally aired 2002-02-25)
+</li>
+<li>
+"I thought you said Tulsa was a three-hour flight."
+"Well, you're forgetting about the time difference."
+("Joey" and "Chandler" in dialog from the episode of <em>Friends</em>
+entitled "The One With Rachel's Phone Number," originally aired 2002-12-05)
+</li>
+<li>
+"Is that a pertinent fact,
+or are you just trying to dazzle me with your command of time zones?"
+(Kelsey Grammer as "Frasier Crane" to "Roz" from the episode of <em>Frasier</em>
+entitled "The Kid," originally aired 1997-11-04)
+</li>
+<li>
+"I put myself and my staff through this crazy, huge ordeal, all because
+I refused to go on at midnight, okay?  And so I work, you know, and
+then I get this job at eleven, supposed to be a big deal.  Then
+yesterday daylight [saving] time ended. Right now it's basically
+midnight." (Conan O'Brien on the 2010-11-08 premiere of <em>Conan</em>.)
+</li>
+<li>
+"The best method, I told folks, was to hang a large clock high on a
+barn wall where all the cows could see it. If you have Holsteins, you
+will need to use an analog clock." (Jerry Nelson, <a
+href="http://www.agriculture.com/family/farm-humor/how-to-adjust-dairy-cows-to-daylight-savings-time">How
+to adjust dairy cows to daylight saving time</a>", <em>Successful Farming</em>,
+2017-10-09.)
+</li>
+<li>
+"And now, driving to California, I find that I must enter a password
+in order to change the time zone on my laptop clock. Evidently,
+someone is out to mess up my schedule and my clock must be secured."
+(Garrison Keillor,
+"<a href="http://www.garrisonkeillor.com/weve-never-been-here-before/">We've
+never been here before</a>", 2017-08-22)
+</li>
+<li>
+"Well, in my time zone that's all the time I have,
+but maybe in your time zone I haven't finished yet. So stay tuned!"
+(Goldie Hawn, <em>Rowan &amp; Martin's Laugh-In</em> No. 65, 1970-03-09)
+</li>
+</ul>
+<h2>See also</h2>
+<ul>
+<li><a href="tz-link.html">Sources for Time Zone and Daylight Saving
+Time Data</a></li>
+</ul>
+<hr>
+<address>
+This web page is in the public domain, so clarified as of
+2009-05-17 by Arthur David Olson.
+<br>
+Please send corrections to this web page to the
+<a href="mailto:tz@iana.org">time zone mailing list</a>.
+</address>
+</body>
+</html>
diff --git a/tz-how-to.html b/tz-how-to.html
new file mode 100644
index 000000000000..a54f54a9689e
--- /dev/null
+++ b/tz-how-to.html
@@ -0,0 +1,682 @@
+<!DOCTYPE html
+	PUBLIC "-//W3C//DTD HTML 4.01//EN"
+	"http://www.w3.org/TR/html4/strict.dtd">
+<html>
+<head>
+<title>How to Read the tz Database</title>
+<meta http-equiv="Content-type" content='text/html; charset="UTF-8"'>
+</head>
+<body>
+<h2>How to Read the <a href="https://en.wikipedia.org/wiki/Tz_database">tz
+Database</a> Source Files</h2>
+<h3>by Bill Seymour</h3>
+<p>This page uses the <code>America/Chicago</code> and
+<code>Pacific/Honolulu</code> zones as examples of how to infer
+times of day from the <a href="tz-link.html">tz database</a>
+source files. It might be helpful, but not absolutely necessary,
+for the reader to have already downloaded the
+latest release of the database and become familiar with the basic layout
+of the data files. The format is explained in the &ldquo;man
+page&rdquo; for the zic compiler, <code>zic.8.txt</code>, in
+the <code>code</code> subdirectory.</p>
+
+<p>We&rsquo;ll begin by talking about the rules for changing between standard
+and daylight saving time since we&rsquo;ll need that information when we talk
+about the zones.</p>
+
+<p>First, let&rsquo;s consider the special daylight saving time rules
+for Chicago (from the <code>northamerica</code> file in
+the <code>data</code> subdirectory):</p>
+
+<table border="1">
+<tr>
+  <th colspan="6">From the Source File</th>
+</tr>
+<tr>
+  <td colspan="6" align="center"><table><tr><td>
+<pre>
+#Rule NAME    FROM TO   TYPE IN  ON      AT   SAVE LETTER
+Rule  Chicago 1920 only  -   Jun 13      2:00 1:00 D
+Rule  Chicago 1920 1921  -   Oct lastSun 2:00 0    S
+Rule  Chicago 1921 only  -   Mar lastSun 2:00 1:00 D
+Rule  Chicago 1922 1966  -   Apr lastSun 2:00 1:00 D
+Rule  Chicago 1922 1954  -   Sep lastSun 2:00 0    S
+Rule  Chicago 1955 1966  -   Oct lastSun 2:00 0    S
+</pre>
+  </td></tr></table></td>
+</tr>
+<tr>
+  <th colspan="6">Reformatted a Bit</th>
+</tr>
+<tr>
+  <th>From</th>
+  <th>To</th>
+  <th colspan="2">On</th>
+  <th>At</th>
+  <th>Action</th>
+</tr>
+<tr align="center">
+  <td colspan="2">1920 only</td>
+  <td colspan="2">June 13<small><sup>th</sup></small></td>
+  <td rowspan="6">02:00 local</td>
+  <td>go to daylight saving time</td>
+</tr>
+<tr align="center">
+  <td>1920</td>
+  <td>1921</td>
+  <td rowspan="5">last Sunday</td>
+  <td>in October</td>
+  <td>return to standard time</td>
+</tr>
+<tr align="center">
+  <td colspan="2">1921 only</td>
+  <td>in March</td>
+  <td rowspan="2">go to daylight saving time</td>
+</tr>
+<tr align="center">
+  <td rowspan="2">1922</td>
+  <td>1966</td>
+  <td>in April</td>
+</tr>
+<tr align="center">
+  <td>1954</td>
+  <td>in September</td>
+  <td rowspan="2">return to standard time</td>
+</tr>
+<tr align="center">
+  <td>1955</td>
+  <td>1966</td>
+  <td>in October</td>
+</tr>
+</table>
+
+<p>We&rsquo;ll basically just ignore the <code>TYPE</code> column.
+In the 2007j release, the most recent as of this writing, the
+<code>TYPE</code> column never contains anything but a hyphen,
+a kind of null value. (From the description in <code>zic.8.txt</code>,
+this appears to be a mechanism for removing years from a set
+in some localizable way. It&rsquo;s used in the file, <code>pacificnew</code>,
+to determine whether a given year will have a US presidential election;
+but everything related to that use is commented out.)
+
+<p>The <code>SAVE</code> column contains the wall clock offset from
+local standard time.
+This is usually either zero for standard time or one hour for daylight
+saving time; but there&rsquo;s no reason, in principle, why it can&rsquo;t
+take on other values.
+
+<p>The <code>LETTER</code> (sometimes called <code>LETTER/S</code>)
+column can contain a variable
+part of the usual abbreviation of the time zone&rsquo;s name, or it can just
+be a hyphen if there&rsquo;s no variable part. For example, the abbreviation
+used in the central time zone will be either &ldquo;CST&rdquo; or
+&ldquo;CDT&rdquo;. The variable part is &lsquo;S&rsquo; or &lsquo;D&rsquo;;
+and, sure enough, that&rsquo;s just what we find in
+the <code>LETTER</code> column
+in the <code>Chicago</code> rules. More about this when we talk about
+&ldquo;Zone&rdquo; lines.
+
+<p>One important thing to notice is that &ldquo;Rule&rdquo; lines
+want at once to be both <i>transitions</i> and <i>steady states</i>:
+<ul>
+<li>On the one hand, they represent transitions between standard and
+daylight saving time; and any number of Rule lines can be in effect
+during a given period (which will always be a non-empty set of
+contiguous calendar years).</li>
+<li>On the other hand, the <code>SAVE</code> and <code>LETTER</code>
+columns contain state that exists between transitions. More about this
+when we talk about the US rules.</li>
+</ul>
+
+<p>In the example above, the transition to daylight saving time
+happened on the 13<small><sup>th</sup></small> of June in 1920, and on
+the last Sunday in March in 1921; but the return to standard time
+happened on the last Sunday in October in both of those
+years. Similarly, the rule for changing to daylight saving time was
+the same from 1922 to 1966; but the rule for returning to standard
+time changed in 1955. Got it?</p>
+
+<p>OK, now for the somewhat more interesting &ldquo;US&rdquo; rules:</p>
+
+<table border="1">
+<tr>
+  <th colspan="6">From the Source File</th>
+</tr>
+<tr>
+  <td colspan="6" align="center"><table><tr><td>
+<pre>
+#Rule NAME FROM TO   TYPE IN  ON        AT   SAVE LETTER/S
+Rule  US   1918 1919  -   Mar lastSun  2:00  1:00 D
+Rule  US   1918 1919  -   Oct lastSun  2:00  0    S
+Rule  US   1942 only  -   Feb 9        2:00  1:00 W # War
+Rule  US   1945 only  -   Aug 14      23:00u 1:00 P # Peace
+Rule  US   1945 only  -   Sep 30       2:00  0    S
+Rule  US   1967 2006  -   Oct lastSun  2:00  0    S
+Rule  US   1967 1973  -   Apr lastSun  2:00  1:00 D
+Rule  US   1974 only  -   Jan 6        2:00  1:00 D
+Rule  US   1975 only  -   Feb 23       2:00  1:00 D
+Rule  US   1976 1986  -   Apr lastSun  2:00  1:00 D
+Rule  US   1987 2006  -   Apr Sun&gt;=1   2:00  1:00 D
+Rule  US   2007 max   -   Mar Sun&gt;=8   2:00  1:00 D
+Rule  US   2007 max   -   Nov Sun&gt;=1   2:00  0    S
+</pre>
+  </td></tr></table></td>
+</tr>
+<tr>
+  <th colspan="6">Reformatted a Bit</th>
+</tr>
+<tr>
+  <th>From</th>
+  <th>To</th>
+  <th colspan="2">On</th>
+  <th>At</th>
+  <th>Action</th>
+</tr>
+<tr align="center">
+  <td rowspan="2">1918</td>
+  <td rowspan="2">1919</td>
+  <td rowspan="2">last Sunday</td>
+  <td>in March</td>
+  <td rowspan="3">02:00 local</td>
+  <td>go to daylight saving time</td>
+</tr>
+<tr align="center">
+  <td>in October</td>
+  <td>return to standard time</td>
+</tr>
+<tr align="center">
+  <td colspan="2">1942 only</td>
+  <td colspan="2">February 9<small><sup>th</sup></small></td>
+  <td>go to &ldquo;war time&rdquo;</td>
+</tr>
+<tr align="center">
+  <td colspan="2" rowspan="2">1945 only</td>
+  <td colspan="2">August 14<small><sup>th</sup></small></td>
+  <td>23:00 <a href="https://en.wikipedia.org/wiki/Universal_Time">UT</a></td>
+  <td>
+    rename &ldquo;war time&rdquo; to &ldquo;peace<br>time;&rdquo;
+    clocks don&rsquo;t change
+  </td>
+</tr>
+<tr align="center">
+  <td colspan="2">September 30<small><sup>th</sup></small></td>
+  <td rowspan="9">02:00 local</td>
+  <td rowspan="2">return to standard time</td>
+</tr>
+<tr align="center">
+  <td rowspan="2">1967</td>
+  <td>2006</td>
+  <td rowspan="2">last Sunday</td>
+  <td>in October</td>
+</tr>
+<tr align="center">
+  <td>1973</td>
+  <td>in April</td>
+  <td rowspan="6">go to daylight saving time</td>
+</tr>
+<tr align="center">
+  <td colspan="2">1974 only</td>
+  <td colspan="2">January 6<small><sup>th</sup></small></td>
+</tr>
+<tr align="center">
+  <td colspan="2">1975 only</td>
+  <td colspan="2">February 23<small><sup>rd</sup></small></td>
+</tr>
+<tr align="center">
+  <td>1976</td>
+  <td>1986</td>
+  <td>last Sunday</td>
+  <td rowspan="2">in April</td>
+</tr>
+<tr align="center">
+  <td>1987</td>
+  <td>2006</td>
+  <td>first Sunday</td>
+</tr>
+<tr align="center">
+  <td rowspan="2">2007</td>
+  <td rowspan="2">present</td>
+  <td colspan="2">second Sunday in March</td>
+</tr>
+<tr align="center">
+  <td colspan="2">first Sunday in November</td>
+  <td>return to standard time</td>
+</tr>
+</table>
+
+<p>There are two interesting things to note here.</p>
+
+<p>First, the time that something happens (in the <code>AT</code>
+column) is not necessarily the local wall clock time. The time can be
+suffixed with &lsquo;s&rsquo; (for &ldquo;standard&rdquo;) to mean
+local standard time (different from wall clock time when observing
+daylight saving time); or it can be suffixed with &lsquo;g&rsquo;,
+&lsquo;u&rsquo;, or &lsquo;z&rsquo;, all three of which mean the
+standard time at the
+<a href="https://en.wikipedia.org/wiki/Prime_Meridian">prime meridian</a>.
+&lsquo;g&rsquo; stands for &ldquo;<a
+href="https://en.wikipedia.org/wiki/Greenwich_Mean_Time">GMT</a>&rdquo;;
+&lsquo;u&rsquo; stands for &ldquo;<a
+href="https://en.wikipedia.org/wiki/Universal_Time">UT</a>&rdquo; or &ldquo;<a
+href="https://en.wikipedia.org/wiki/Coordinated_Universal_Time">UTC</a>&rdquo;
+(whichever was official at the time); &lsquo;z&rsquo; stands for the
+<a href="https://en.wikipedia.org/wiki/Nautical_time">nautical time zone</a>
+Z (a.k.a. &ldquo;Zulu&rdquo; which, in turn, stands for &lsquo;Z&rsquo;).
+The time can also be suffixed with &lsquo;w&rsquo; meaning &ldquo;wall
+clock time;&rdquo; but it usually isn&rsquo;t because that&rsquo;s the
+default.</p>
+
+<p>Second, the day in the <code>ON</code> column, in addition to
+&ldquo;<code>lastSun</code>&rdquo; or a particular day of the month,
+can have the form, &ldquo;<code>Sun&gt;=</code><i>x</i>&rdquo; or
+&ldquo;<code>Sun&lt;=</code><i>x</i>,&rdquo; where <i>x</i> is a day
+of the month. For example, &ldquo;<code>Sun&gt;=8</code>&rdquo; means
+&ldquo;the first Sunday on or after the eighth of the month,&rdquo; in
+other words, the second Sunday of the month. Furthermore, although
+there are no examples above, the weekday needn&rsquo;t be
+&ldquo;<code>Sun</code>&rdquo; in either form, but can be the usual
+three-character English abbreviation for any day of the week.</p>
+
+<p>And the US rules give us more examples of a couple of things
+already mentioned:</p>
+
+<ul>
+<li>The rules for changing to and from daylight saving time are
+actually <i>different sets</i> of rules; and the two sets can change
+independently. Consider, for example, that the rule for the return to
+standard time stayed the same from 1967 to 2006; but the rule for the
+transition to daylight saving time changed several times in the same
+period.  There can also be periods, 1946 to 1966 for example, when no
+rule from this group is in effect, and so either no transition
+happened in those years, or some other rule is in effect (perhaps a
+state or other more local rule).</li>
+
+<li>The <code>SAVE</code> and <code>LETTER</code> columns
+contain <i>steady state</i>, not transitions. Consider, for example,
+the transition from &ldquo;war time&rdquo; to &ldquo;peace time&rdquo;
+that happened on August 14, 1945. The &ldquo;1:00&rdquo; in
+the <code>SAVE</code> column is <i>not</i> an instruction to advance
+the clock an hour. It means that clocks should <i>be</i> one hour
+ahead of standard time, which they already are because of the previous
+rule, so there should be no change.</li>
+
+</ul>
+
+<p>OK, now let&rsquo;s look at a Zone record:</p>
+
+<table border="1">
+<tr>
+  <th colspan="5">From the Source File</th>
+</tr>
+<tr>
+  <td colspan="6" align="center"><table><tr><td>
+<pre>
+#Zone       NAME      GMTOFF   RULES FORMAT [UNTIL]
+Zone  America/Chicago -5:50:36 -       LMT  1883 Nov 18 12:09:24
+                      -6:00    US      C%sT 1920
+                      -6:00    Chicago C%sT 1936 Mar  1  2:00
+                      -5:00    -       EST  1936 Nov 15  2:00
+                      -6:00    Chicago C%sT 1942
+                      -6:00    US      C%sT 1946
+                      -6:00    Chicago C%sT 1967
+                      -6:00    US      C%sT
+</pre>
+  </td></tr></table></td>
+</tr>
+<tr>
+  <th colspan="5">Columns Renamed</th>
+</tr>
+<tr>
+  <th rowspan="2">Standard Offset<br>
+    from <a href="https://en.wikipedia.org/wiki/Prime_Meridian">Prime
+    Meridian</a></th>
+  <th rowspan="2">Daylight<br>Saving Time</th>
+  <th rowspan="2">Abbreviation(s)</th>
+  <th colspan="2">Ending at Local Time</th>
+</tr>
+<tr>
+  <th>Date</th>
+  <th>Time</th>
+</tr>
+<tr align="center">
+  <td>&minus;5:50:36</td>
+  <td>not observed</td>
+  <td>LMT</td>
+  <td>1883-11-18</td>
+  <td>12:09:24</td>
+</tr>
+<tr align="center">
+  <td rowspan="2">&minus;6:00:00</td>
+  <td>US rules</td>
+  <td rowspan="2">CST or CDT</td>
+  <td>1920-01-01</td>
+  <td>00:00:00</td>
+</tr>
+<tr align="center">
+  <td>Chicago rules</td>
+  <td>1936-03-01</td>
+  <td rowspan="2">02:00:00</td>
+</tr>
+<tr align="center">
+  <td>&minus;5:00:00</td>
+  <td>not observed</td>
+  <td>EST</td>
+  <td>1936-11-15</td>
+</tr>
+<tr align="center">
+  <td rowspan="4">&minus;6:00:00</td>
+  <td>Chicago rules</td>
+  <td>CST or CDT</td>
+  <td>1942-01-01</td>
+  <td rowspan="3">00:00:00</td>
+</tr>
+<tr align="center">
+  <td>US rules</td>
+  <td>CST, CWT or CPT</td>
+  <td>1946-01-01</td>
+</tr>
+<tr align="center">
+  <td>Chicago rules</td>
+  <td rowspan="2">CST or CDT</td>
+  <td>1967-01-01</td>
+</tr>
+<tr align="center">
+  <td>US rules</td>
+  <td colspan="2">&mdash;</td>
+</tr>
+</table>
+
+<p>There are a couple of interesting differences between Zones and Rules.</p>
+
+<p>First, and somewhat trivially, whereas Rules are considered to
+contain one or more records, a Zone is considered to be a single
+record with zero or more <i>continuation lines</i>. Thus, the keyword,
+&ldquo;<code>Zone</code>,&rdquo; and the zone name are not
+repeated. The last line is the one without anything in
+the <code>[UNTIL]</code> column.</p>
+
+<p>Second, and more fundamentally, each line of a Zone represents a
+steady state, not a transition between states. The state exists from
+the date and time in the previous line&rsquo;s <code>[UNTIL]</code>
+column up to the date and time in the current
+line&rsquo;s <code>[UNTIL]</code> column. In other words, the date and
+time in the <code>[UNTIL]</code> column is the instant that separates
+this state from the next. Where that would be ambiguous because
+we&rsquo;re setting our clocks back, the <code>[UNTIL]</code> column
+specifies the first occurrence of the instant. The state specified by
+the last line, the one without anything in the <code>[UNTIL]</code>
+column, continues to the present.</p>
+
+<p>The first line typically specifies the mean solar time observed
+before the introduction of standard time. Since there&rsquo;s no line before
+that, it has no beginning. <code>8-) </code> For some places near the <a
+href="https://en.wikipedia.org/wiki/International_Date_Line">International
+Date Line</a>, the first <i>two</i> lines will show solar times
+differing by 24 hours; this corresponds to a movement of the Date
+Line.  For example:</p>
+
+<pre>
+#Zone NAME          GMTOFF   RULES FORMAT [UNTIL]
+Zone America/Juneau 15:02:19 -     LMT    1867 Oct 18
+                    -8:57:41 -     LMT    ...
+</pre>
+
+<p>When Alaska was purchased from Russia in 1867, the Date Line moved
+from the Alaska/Canada border to the Bering Strait; and the time in
+Alaska was then 24 hours earlier than it had
+been. <code>&lt;aside&gt;</code>(6 October in the Julian calendar,
+which Russia was still using then for religious reasons, was followed
+by <i>a second instance of the same day with a different name</i>, 18
+October in the Gregorian calendar. Isn&rsquo;t civil time
+wonderful? <code>8-)</code>)<code>&lt;/aside&gt;</code></p>
+
+<p>The abbreviation, &ldquo;LMT&rdquo; stands for &ldquo;local mean
+time&rdquo;, which is an invention of
+the <a href="https://en.wikipedia.org/wiki/Tz_database">tz
+database</a> and was probably never actually used during the
+period. Furthermore, the value is almost certainly wrong except in the
+archetypal place after which the zone is named. (The tz database
+usually doesn&rsquo;t provide a separate Zone record for places where
+nothing significant happened after 1970.)</p>
+
+<p>The <code>RULES</code> column tells us whether daylight saving time is being observed:
+<ul>
+<li>A hyphen, a kind of null value, means that we have not set our
+clocks ahead of standard time.</li>
+
+<li>An amount of time (usually but not necessarily &ldquo;1:00&rdquo;
+meaning one hour) means that we have set our clocks ahead by that
+amount.</li>
+
+<li>Some alphabetic string means that we <i>might have</i> set our
+clocks ahead; and we need to check the rule the name of which is the
+given alphabetic string.</li>
+</ul>
+
+<p>An example of a specific amount of time is:</p>
+<pre>
+#Zone NAME            GMTOFF RULES FORMAT [UNTIL]
+Zone Pacific/Honolulu ...                 1933 Apr 30 2:00
+                      -10:30 1:00  HDT    1933 May 21 2:00
+                      ...
+</pre>
+
+<p>Hawaii tried daylight saving time for three weeks in 1933 and
+decided they didn&rsquo;t like it. <code>8-) </code>Note that
+the <code>GMTOFF</code> column always contains the standard time
+offset, so the wall clock time during this period was GMT &minus;
+10:30 + 1:00 = GMT &minus; 9:30.</p>
+
+<p>The <code>FORMAT</code> column specifies the usual abbreviation of
+the time zone name. It can have one of three forms:</p>
+<ul>
+
+<li>a string of three or more characters that are either ASCII alphanumerics,
+&ldquo;<code>+</code>&rdquo;, or &ldquo;<code>-</code>&rdquo;,
+in which case that&rsquo;s the abbreviation</li>
+
+<li>a pair of strings separated by a slash
+(&lsquo;<code>/</code>&rsquo;), in which case the first string is the
+abbreviation for the standard time name and the second string is the
+abbreviation for the daylight saving time name</li>
+
+<li>a string containing &ldquo;<code>%s</code>,&rdquo; in which case
+the &ldquo;<code>%s</code>&rdquo; will be replaced by the text in the
+appropriate Rule&rsquo;s <code>LETTER</code> column</li>
+</ul>
+
+<p>The last two make sense only if there&rsquo;s a named rule in effect.</p>
+
+<p>An example of a slash is:</p>
+<pre>
+#Zone NAME          GMTOFF RULES FORMAT  [UNTIL]
+Zone  Europe/London ...                  1996
+                    0:00   EU    GMT/BST
+</pre>
+
+<p>The current time in the UK is called either Greenwich mean time or
+British summer time.</p>
+
+<p>One wrinkle, not fully explained in <code>zic.8.txt</code>, is what
+happens when switching to a named rule. To what values should
+the <code>SAVE</code> and <code>LETTER</code> data be initialized?</p>
+
+<ul>
+<li>If at least one transition has happened, use
+the <code>SAVE</code> and <code>LETTER</code> data from the most
+recent.</li>
+
+<li>If switching to a named rule before any transition has happened,
+assume standard time (<code>SAVE</code> zero), and use
+the <code>LETTER</code> data from the earliest transition with
+a <code>SAVE</code> of zero.
+
+</ul>
+
+<p>And three last things about the <code>FORMAT</code> column:</p>
+<ul>
+
+<li>The <a href="https://en.wikipedia.org/wiki/Tz_database">tz
+database</a> gives abbreviations for time zone names in <i>popular
+usage</i>, which is not necessarily &ldquo;correct&rdquo; by law. For
+example, the last line in
+<code>Zone</code> <code>Pacific/Honolulu</code> (shown below) gives
+&ldquo;HST&rdquo; for &ldquo;Hawaii standard time&rdquo; even though the
+<a href="https://www.law.cornell.edu/uscode/text/15/263">legal</a>
+name for that time zone is &ldquo;Hawaii-Aleutian standard time.&rdquo;
+This author has read that there are also some places in Australia where
+popular time zone names differ from the legal ones.
+
+<li>No attempt is made to <a
+href="https://en.wikipedia.org/wiki/Internationalization_and_localization">localize</a>
+the abbreviations. They are intended to be the values returned through the
+<code>"%Z"</code> format specifier to
+<a href="https://en.wikipedia.org/wiki/C_(programming_language)">C</a>&rsquo;s
+<a href="http://pubs.opengroup.org/onlinepubs/9699919799/functions/strftime.html"><code>strftime</code></a>
+function in the
+<a href="http://kirste.userpage.fu-berlin.de/chemnet/use/info/libc/libc_19.html#SEC324">&ldquo;C&rdquo; locale</a>.
+
+<li>If there is no generally-accepted abbreviation for a time zone,
+a numeric offset is used instead, e.g., <code>+07</code> for 7 hours
+ahead of Greenwich. By convention, <code>-00</code> is used in a
+zone while uninhabited, where the offset is zero but in some sense
+the true offset is undefined.
+</ul>
+
+<p>As a final example, here&rsquo;s the complete history for Hawaii:</p>
+
+<table border="1">
+<tr>
+  <th colspan="6">Relevant Excerpts from the US Rules</th>
+</tr>
+<tr>
+  <td colspan="6" align="center"><table><tr><td>
+<pre>
+#Rule NAME FROM TO   TYPE IN  ON      AT     SAVE LETTER/S
+Rule  US   1918 1919 -    Oct lastSun  2:00  0    S
+Rule  US   1942 only -    Feb  9       2:00  1:00 W # War
+Rule  US   1945 only -    Aug 14      23:00u 1:00 P # Peace
+Rule  US   1945 only -    Sep 30       2:00  0    S
+</pre>
+  </td></tr></table></td>
+</tr>
+<tr>
+  <th colspan="6">The Zone Record</th>
+</tr>
+<tr>
+  <td colspan="6" align="center"><table><tr><td>
+<pre>
+#Zone NAME            GMTOFF    RULES FORMAT [UNTIL]
+Zone Pacific/Honolulu -10:31:26 -     LMT    1900 Jan  1 12:00
+                      -10:30    -     HST    1933 Apr 30  2:00
+                      -10:30    1:00  HDT    1933 May 21  2:00
+                      -10:30    US    H%sT   1947 Jun  8  2:00
+                      -10:00    -     HST
+</pre>
+  </td></tr></table></td>
+</tr>
+<tr>
+  <th colspan="6">What We Infer</th>
+</tr>
+<tr>
+  <th rowspan="2">Wall-Clock<br>Offset from<br>Prime Meridian</th>
+  <th rowspan="2">Adjust<br>Clocks</th>
+  <th colspan="2">Time Zone</th>
+  <th colspan="2">Ending at Local Time</th>
+</tr>
+<tr>
+  <th>Abbrv.</th>
+  <th>Name</th>
+  <th>Date</th>
+  <th>Time</th>
+</tr>
+<tr align="center">
+  <td>&minus;10:31:26</td>
+  <td>&mdash;</td>
+  <td>LMT</td>
+  <td>local mean time</td>
+  <td>1900-01-01</td>
+  <td>12:00</td>
+</tr>
+<tr align="center">
+  <td>&minus;10:30</td>
+  <td>+0:01:26</td>
+  <td>HST</td>
+  <td>Hawaii standard time</td>
+  <td>1933-04-30</td>
+  <td rowspan="3">02:00</td>
+</tr>
+<tr align="center">
+  <td>&minus;9:30</td>
+  <td>+1:00</td>
+  <td>HDT</td>
+  <td>Hawaii daylight time</td>
+  <td>1933-05-21</td>
+</tr>
+<tr align="center">
+  <td>&minus;10:30&sup1;</td>
+  <td>&minus;1:00&sup1;</td>
+  <td>HST&sup1;</td>
+  <td>Hawaii standard time</td>
+  <td>1942-02-09</td>
+</tr>
+<tr align="center">
+  <td rowspan="2">&minus;9:30</td>
+  <td>+1:00</td>
+  <td>HWT</td>
+  <td>Hawaii war time</td>
+  <td>1945-08-14</td>
+  <td>13:30&sup2;</td>
+</tr>
+<tr align="center">
+  <td>0</td>
+  <td>HPT</td>
+  <td>Hawaii peace time</td>
+  <td>1945-09-30</td>
+  <td rowspan="2">02:00</td>
+</tr>
+<tr align="center">
+  <td>&minus;10:30</td>
+  <td>&minus;1:00</td>
+  <td rowspan="2">HST</td>
+  <td rowspan="2">Hawaii standard time</td>
+  <td>1947-06-08</td>
+</tr>
+<tr align="center">
+  <td>&minus;10:00&sup3;</td>
+  <td>+0:30&sup3;</td>
+  <td colspan="2">&mdash;</td>
+</tr>
+<tr>
+  <td colspan="6">
+    &sup1;Switching to US rules&hellip;most recent transition (in 1919) was to standard time
+  </td>
+</tr>
+<tr>
+  <td colspan="6">
+    &sup2;23:00 <a href="https://en.wikipedia.org/wiki/Universal_Time">UT</a>
+    + (&minus;9:30) = 13:30 local
+  </td>
+</tr>
+<tr>
+  <td colspan="6">
+    &sup3;Since <a href="https://en.wikipedia.org/wiki/ISO_8601">1947&ndash;06&ndash;08T12:30Z</a>,
+    the civil time in Hawaii has been
+    <a href="https://en.wikipedia.org/wiki/Universal_Time">UT</a>/<a href="https://en.wikipedia.org/wiki/Coordinated_Universal_Time">UTC</a>
+    &minus; 10:00 year-round.
+  </td>
+</tr>
+</table>
+
+<p>There will be a short quiz later. <code>8-)</code></p>
+
+<hr>
+<address>
+This web page is in the public domain, so clarified as of
+2015-10-20 by Bill Seymour.
+<br>
+All suggestions and corrections will be welcome; all flames will be amusing.
+Mail to was at pobox dot com.
+</address>
+</body>
+</html>
diff --git a/tz-link.html b/tz-link.html
new file mode 100644
index 000000000000..13a824d7e9af
--- /dev/null
+++ b/tz-link.html
@@ -0,0 +1,953 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+<title>Sources for time zone and daylight saving time data</title>
+<meta charset="UTF-8">
+</head>
+<body>
+<h1>Sources for time zone and daylight saving time data</h1>
+<p>
+<a href="https://en.wikipedia.org/wiki/Time_zone">Time zone</a> and
+<a href="https://en.wikipedia.org/wiki/Daylight_saving_time">daylight-saving</a>
+rules are controlled by individual
+governments. They are sometimes changed with little notice, and their
+histories and planned futures are often recorded only fitfully. Here
+is a summary of attempts to organize and record relevant data in this
+area.
+</p>
+<h2 id="tzdb">The <code><abbr title="time zone">tz</abbr></code> database</h2>
+<p>
+The <a href="https://en.wikipedia.org/wiki/Public_domain">public-domain</a>
+time zone database contains code and data
+that represent the history of local time
+for many representative locations around the globe.
+It is updated periodically to reflect changes made by political bodies
+to time zone boundaries and daylight saving rules.
+This database (known as <code><abbr>tz</abbr></code>,
+<code><abbr>tzdb</abbr></code>, or <code>zoneinfo</code>)
+is used by several implementations,
+including
+<a href="https://www.gnu.org/software/libc/">the
+<abbr title="GNU's Not Unix">GNU</abbr>
+C Library</a> (used in
+<a href="https://en.wikipedia.org/wiki/Linux"><abbr>GNU</abbr>/Linux</a>),
+<a href="https://www.android.com">Android</a>,
+<a href="https://developer.mozilla.org/en-US/docs/Mozilla/B2G_OS">B2G
+<abbr title="Operating System">OS</abbr></a>,
+<a href="https://www.freebsd.org">Free<abbr
+title="Berkeley Software Distribution">BSD</abbr></a>,
+<a href="https://netbsd.org">Net<abbr>BSD</abbr></a>,
+<a href="https://www.openbsd.org">Open<abbr>BSD</abbr></a>,
+<a href="https://www.chromium.org/chromium-os">Chromium OS</a>,
+<a href="https://cygwin.com">Cygwin</a>,
+<a href="http://www.delorie.com/djgpp/"><abbr
+title="DJ's GNU Programming Platform">DJGPP</abbr></a>,
+<a href="https://en.wikipedia.org/wiki/MINIX">MINIX</a>,
+<a href="https://www.mysql.com">MySQL</a>,
+<a href="https://en.wikipedia.org/wiki/WebOS"><abbr
+title="Web Operating System">webOS</abbr></a>,
+<a href="https://ibm.com/aix"><abbr
+title="Advanced Interactive eXecutive">AIX</abbr></a>,
+<a href="https://en.wikipedia.org/wiki/BlackBerry_10">BlackBerry 10</a>,
+<a href="https://www.apple.com/ios/"><abbr
+title="iPhone OS">iOS</abbr></a>,
+<a href="https://www.apple.com/macos/">macOS</a>,
+<a href="https://www.microsoft.com/en-us/windows">Microsoft Windows</a>,
+<a href="https://www.hpe.com/info/openvms">Open<abbr
+title="Virtual Memory System">VMS</abbr></a>,
+<a href="https://www.oracle.com/database/index.html">Oracle Database</a>, and
+<a href="https://www.oracle.com/solaris">Oracle Solaris</a>.</p>
+<p>
+Each location in the database represents a region where all
+clocks keeping local time have agreed since 1970.
+Locations are identified by continent or ocean and then by the name of
+the location, which is typically the largest city within the region.
+For example, <code>America/New_York</code>
+represents most of the <abbr title="United States">US</abbr> eastern time zone;
+<code>America/Phoenix</code> represents most of Arizona, which
+uses mountain time without daylight saving time (<abbr
+title="daylight saving time">DST</abbr>);
+<code>America/Detroit</code> represents most of Michigan, which uses
+eastern time but with different <abbr>DST</abbr> rules in 1975;
+and other entries represent smaller regions like Starke County,
+Indiana, which switched from central to eastern time in 1991
+and switched back in 2006.
+To use the database on an extended <a
+href="https://en.wikipedia.org/wiki/POSIX"><abbr
+title="Portable Operating System Interface">POSIX</abbr></a>
+implementation set the <code><abbr>TZ</abbr></code>
+environment variable to the location's full name,
+e.g., <code><abbr>TZ</abbr>="America/New_York"</code>.</p>
+<p>
+Associated with each region is a history of offsets from
+<a href="https://en.wikipedia.org/wiki/Universal_Time">Universal
+Time</a> (<abbr>UT</abbr>), which is <a
+href="https://en.wikipedia.org/wiki/Greenwich_Mean_Time">Greenwich Mean
+Time</a> (<abbr>GMT</abbr>) with days beginning at midnight;
+for time stamps after 1960 this is more precisely <a
+href="https://en.wikipedia.org/wiki/Coordinated_Universal_Time">Coordinated
+Universal Time</a> (<abbr>UTC</abbr>).
+The database also records when daylight saving time was in use,
+along with some time zone abbreviations such as <abbr>EST</abbr>
+for Eastern Standard Time in the <abbr>US</abbr>.</p>
+<h2 id="download">Downloading the <code><abbr>tz</abbr></code> database</h2>
+<p>
+The following <a
+href="https://en.wikipedia.org/wiki/Unix_shell">shell</a> commands download
+the latest release's two
+<a href="https://en.wikipedia.org/wiki/Tar_(computing)">tarballs</a>
+to a <abbr>GNU</abbr>/Linux or similar host.</p>
+<pre style="margin-left: 2em"><code>mkdir tzdb
+cd tzdb
+<a href="https://www.gnu.org/software/wget/">wget</a> https://www.iana.org/time-zones/repository/tzcode-latest.tar.gz
+wget https://www.iana.org/time-zones/repository/tzdata-latest.tar.gz
+<a href="https://www.gnu.org/software/gzip/">gzip</a> -dc tzcode-latest.tar.gz | <a href="https://www.gnu.org/software/tar/">tar</a> -xf -
+gzip -dc tzdata-latest.tar.gz | tar -xf -
+</code></pre>
+<p>Alternatively, the following shell commands download the same
+release in a single-tarball format containing extra data
+useful for regression testing:</p>
+<pre style="margin-left: 2em"><code>wget <a href="https://www.iana.org/time-zones/repository/tzdb-latest.tar.lz">https://www.iana.org/time-zones/repository/tzdb-latest.tar.lz</a>
+<a href="https://www.nongnu.org/lzip/">lzip</a> -dc tzdb-latest.tar.lz | tar -xf -
+</code></pre>
+<p>These commands use convenience links to the latest release
+of the <code><abbr>tz</abbr></code> database hosted by the
+<a href="https://www.iana.org/time-zones">Time Zone Database website</a>
+of the <a href="https://www.iana.org">Internet Assigned Numbers
+Authority (IANA)</a>.
+Older releases are in files named
+<code>tzcode<var>V</var>.tar.gz</code>,
+<code>tzdata<var>V</var>.tar.gz</code>, and
+<code>tzdb-<var>V</var>.tar.lz</code>,
+where <code><var>V</var></code> is the version.
+Since 1996, each version has been a four-digit year followed by
+lower-case letter (<samp>a</samp> through <samp>z</samp>,
+then <samp>za</samp> through <samp>zz</samp>, then <samp>zza</samp>
+through <samp>zzz</samp>, and so on).
+Since version 2016h, each release has contained a text file named
+"<samp>version</samp>" whose first (and currently only) line is the version.
+The releases are also available in an
+<a href="ftp://ftp.iana.org/tz/releases/"><abbr
+title="File Transfer Protocol">FTP</abbr> directory</a> via a
+less-secure protocol.</p>
+<p>Alternatively, a development repository of code and data can be
+retrieved from <a href="https://github.com">GitHub</a> via the shell
+command:</p>
+<pre style="margin-left: 2em"><code><a href="https://git-scm.com">git</a> clone <a href="https://github.com/eggert/tz">https://github.com/eggert/tz</a>
+</code></pre>
+<p>
+Since version 2012e, each release has been tagged in development repositories.
+Untagged commits are less well tested and probably contain
+more errors.</p>
+<p>
+After obtaining the code and data files, see the
+<code>README</code> file for what to do next.
+The code lets you compile the <code><abbr>tz</abbr></code> source files into
+machine-readable binary files, one for each location. It also lets
+you read a <code><abbr>tz</abbr></code> binary file and interpret time stamps for that
+location.</p>
+<h2 id="changes">Changes to the <code><abbr>tz</abbr></code> database</h2>
+<p>
+The <code><abbr>tz</abbr></code> code and data
+are by no means authoritative. If you find errors, please
+send changes to <a href="mailto:tz@iana.org"><code>tz@iana.org</code></a>,
+the time zone mailing list. You can also <a
+href="https://mm.icann.org/mailman/listinfo/tz">subscribe</a> to it
+and browse the <a
+href="https://mm.icann.org/pipermail/tz/">archive of old
+messages</a>.</p>
+<p>
+If your government plans to change its time zone boundaries or
+daylight saving rules, inform <code>tz@iana.org</code> well in
+advance, as this will coordinate updates to many cell phones,
+computers, and other devices around the world. With
+less than a year's notice there is a good chance that some
+computer-based clocks will operate incorrectly after the change, due
+to delays in propagating updates to software and data. The shorter
+the notice, the more likely clock problems will arise; see "<a
+href="https://codeofmatt.com/2016/04/23/on-the-timing-of-time-zone-changes/">On
+the Timing of Time Zone Changes</a>" for examples.
+</p>
+<p>
+Changes to the <code><abbr>tz</abbr></code> code and data are often
+propagated to clients via operating system updates, so
+client <code><abbr>tz</abbr></code> data can often be corrected by
+applying these updates. With GNU/Linux and similar systems, if your
+maintenance provider has not yet adopted the
+latest <code><abbr>tz</abbr></code> data, you can often short-circuit
+the process by tailoring the generic instructions in
+the <code><abbr>tz</abbr> README</code> file and installing the latest
+data yourself. System-specific instructions for installing the
+latest <code><abbr>tz</abbr></code> data have also been published
+for <a href="https://www.ibm.com/developerworks/aix/library/au-aix-olson-time-zone/index.html"><abbr>AIX</abbr></a>,
+<a
+href="https://play.google.com/store/apps/details?id=com.google.android.timezone.data">Android</a>,
+<a
+href="http://userguide.icu-project.org/datetime/timezone"><abbr
+title="International Components for Unicode">ICU</abbr></a>,
+<a href="https://developer.ibm.com/javasdk/support/dst/jtzu/"><abbr>IBM</abbr></a>
+and <a
+href="http://www.oracle.com/technetwork/java/javase/tzupdater-readme-136440.html">Oracle</a>
+Java, <a href="http://www.joda.org/joda-time/tz_update.html">Joda-Time</a>, <a
+href="https://dev.mysql.com/doc/refman/en/time-zone-support.html">MySQL</a>,
+and <a
+href="https://nodatime.org/userguide/tzdb">Noda Time</a> (see below).
+</p>
+<p>Sources for the <code><abbr>tz</abbr></code> database are
+<a href="https://en.wikipedia.org/wiki/UTF-8"><abbr
+title="Unicode Transformation Format 8-bit">UTF-8</abbr></a>
+<a href="https://en.wikipedia.org/wiki/Text_file">text files</a>
+with lines terminated by <a href="https://en.wikipedia.org/wiki/Newline"><abbr
+title="linefeed">LF</abbr></a>,
+which can be modified by common text editors such
+as <a href="https://www.gnu.org/software/emacs/">GNU Emacs</a>,
+<a href="https://wiki.gnome.org/Apps/Gedit">gedit</a>, and
+<a href="https://www.vim.org">vim</a>.
+Specialized source-file editing can be done via the
+<a href="https://packagecontrol.io/packages/zoneinfo">Sublime
+zoneinfo</a> package for <a
+href="https://www.sublimetext.com">Sublime Text</a> and the <a
+href="https://marketplace.visualstudio.com/items?itemName=gilmoreorless.vscode-zoneinfo">VSCode
+zoneinfo</a> extension for <a href="https://code.visualstudio.com">Visual
+Studio Code</a>.
+</p>
+<p>
+For further information about updates, please see
+<a href="https://tools.ietf.org/html/rfc6557">Procedures for
+Maintaining the Time Zone Database</a> (Internet <abbr
+title="Request For Comments">RFC</abbr> 6557). More detail can be
+found in <a href="theory.html">Theory and pragmatics of the tz code and data</a>.
+</p>
+<h2 id="commentary">Commentary on the <code><abbr>tz</abbr></code> database</h2>
+<ul>
+<li>The article
+<a href="https://en.wikipedia.org/wiki/Tz_database">tz database</a> is
+an encyclopedic summary.</li>
+<li><a href="tz-how-to.html">How to Read the
+tz Database Source Files</a> explains the <code><abbr>tz</abbr></code>
+database format.</li>
+<li><a
+href="https://blog.jonudell.net/2009/10/23/a-literary-appreciation-of-the-olsonzoneinfotz-database/">A
+literary appreciation of the Olson/Zoneinfo/tz database</a> comments on the
+database's style.</li>
+</ul>
+<h2 id="web">Web sites using recent versions of the
+<code><abbr>tz</abbr></code> database</h2>
+<p>
+These are listed roughly in ascending order of complexity and fanciness.
+</p>
+<ul>
+<li><a href="https://time.is">Time.is</a> shows locations'
+time and zones.</li>
+<li><a href="https://www.timejones.com">TimeJones.com</a>,
+<a href="https://timezoneconverterapp.com">Time Zone Converter</a> and
+<a href="http://worldclock.com">The World Clock</a>
+are time zone converters.</li>
+<li><a
+href="http://twiki.org/cgi-bin/xtra/tzdatepick.html">Date and Time Gateway</a>
+lets you see the <code><abbr>TZ</abbr></code> values directly.</li>
+<li><a
+href="http://www.convertit.com/Go/ConvertIt/World_Time/Current_Time.ASP">Current
+Time in 1000 Places</a> uses descriptions of the values.</li>
+<li><a href="http://www.timezoneconverter.com/cgi-bin/tzc.tzc">Time Zone
+Converter</a>
+uses a pulldown menu.</li>
+<li><a href="http://home.kpn.nl/vanadovv/time/TZworld.html">Complete
+timezone information for all countries</a> displays tables of DST rules.
+<li><a href="https://www.timeanddate.com/worldclock/">The World Clock &ndash;
+Worldwide</a> lets you sort zone names and convert times.</li>
+<li><a href="https://24timezones.com">24TimeZones</a> has a world
+time map and a time converter.</li>
+<li><a href="https://www.zeitverschiebung.net/en/">Time Difference</a>
+calculates the current time difference between locations.</li>
+<li><a href="http://www.wx-now.com">Weather Now</a> and
+<a href="http://www.thetimenow.com">The Time Now</a> list the weather too.</li>
+</ul>
+<h2 id="protocols">Network protocols for <code><abbr>tz</abbr></code> data</h2>
+<ul>
+<li>The <a href="https://www.ietf.org">Internet Engineering Task Force</a>'s
+<a href="https://datatracker.ietf.org/wg/tzdist/charter/">Time Zone Data
+Distribution Service (tzdist) working group</a> defined <a
+href="https://tools.ietf.org/html/rfc7808">TZDIST</a>
+(Internet <abbr>RFC</abbr> 7808), a time zone data distribution service,
+along with <a href="https://tools.ietf.org/html/rfc7809">CalDAV</a>
+(Internet <abbr>RFC</abbr> 7809), a calendar access protocol for
+transferring time zone data by reference. The draft <a
+id="TZDIST-Geolocate"
+href="https://tools.ietf.org/html/draft-murchison-tzdist-geolocate-01">TZDIST
+Geolocate Extension</a> lets a client determine its time zone region
+from its geographic location using a <a
+href="https://tools.ietf.org/html/rfc5870">'geo' URI</a>.</li>
+<li>The <a href="https://tools.ietf.org/html/rfc5545">
+Internet Calendaring and Scheduling Core Object Specification
+(iCalendar)</a> (Internet <abbr>RFC</abbr> 5445)
+covers time zone
+data; see its VTIMEZONE calendar component.
+The iCalendar format requires specialized parsers and generators; a
+variant <a href="https://tools.ietf.org/html/rfc6321">xCal</a>
+(Internet <abbr>RFC</abbr> 6321) uses
+<a href="https://www.w3.org/XML/"><abbr
+title="Extensible Markup Language">XML</abbr></a> format, and a variant
+<a href="https://tools.ietf.org/html/rfc7265">jCal</a>
+(Internet <abbr>RFC</abbr> 7265)
+uses <a href="https://www.json.org"><abbr
+title="JavaScript Object Notation">JSON</abbr></a> format.</li>
+</ul>
+<h2 id="compilers">Other <code><abbr>tz</abbr></code> compilers</h2>
+<ul>
+<li><a href="https://sourceforge.net/projects/vzic/">Vzic</a> is a <a
+href="https://en.wikipedia.org/wiki/C_%28programming_language%29">C</a>
+program that compiles
+<code><abbr>tz</abbr></code> source into iCalendar-compatible VTIMEZONE files.
+Vzic is freely
+available under the <a
+href="https://www.gnu.org/copyleft/gpl.html"><abbr>GNU</abbr>
+General Public License (<abbr
+title="General Public License">GPL</abbr>)</a>.</li>
+<li><a href="https://sourceforge.net/projects/tzical/">tziCal &ndash; tz
+database conversion utility</a> is like Vzic, except for the <a
+href="https://www.microsoft.com/net">.NET framework</a>
+and with a <abbr>BSD</abbr>-style license.</li>
+<li><a
+href="http://search.cpan.org/dist/DateTime-TimeZone/">DateTime::TimeZone</a>
+contains a script <code>parse_olson</code> that compiles
+<code><abbr>tz</abbr></code> source into <a href="https://www.perl.org">Perl</a>
+modules. It is part of the Perl <a
+href="http://datetime.perl.org">DateTime Project</a>, which is freely
+available under both the <abbr>GPL</abbr> and the Perl Artistic
+License. DateTime::TimeZone also contains a script
+<code>tests_from_zdump</code> that generates test cases for each clock
+transition in the <code><abbr>tz</abbr></code> database.</li>
+<li>The <a href="https://howardhinnant.github.io/date/tz.html">Time Zone
+Database Parser</a> is a
+<a href="https://en.wikipedia.org/wiki/C%2B%2B">C++</a> parser and
+runtime library that is <a
+href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2017/p0355r4.html">moving
+forward</a> for inclusion in the next iteration of <a
+href="https://isocpp.org/std/the-standard"><em><abbr
+title="International Organization for Standardization">ISO</abbr>
+International Standard ISO/IEC 14882:2017(E) &ndash; Programming
+Language C++</em></a>.
+It is freely available under the
+<abbr title="Massachusetts Institute of Technology">MIT</abbr> license.</li>
+<li><a id="ICU" href="http://site.icu-project.org">International Components for
+Unicode (<abbr>ICU</abbr>)</a> contains C/C++ and <a
+href="https://en.wikipedia.org/wiki/Java_%28programming_language%29">Java</a>
+libraries for internationalization that
+has a compiler from <code><abbr>tz</abbr></code> source
+and from <abbr title="Common Locale Data Repository">CLDR</abbr> data
+(mentioned <a href="#CLDR">below</a>)
+into an <abbr>ICU</abbr>-specific format.
+<abbr>ICU</abbr> is freely available under a
+<abbr>BSD</abbr>-style license.</li>
+<li>The <a href="https://github.com/lau/tzdata">Tzdata</a> package for
+the <a href="https://elixir-lang.org">Elixir</a> language downloads
+and compiles tz source and exposes <abbr
+title="Application Program Interface">API</abbr>s for use. It is
+freely available under the <abbr>MIT</abbr> license.</li>
+<li>Java-based compilers and libraries include:
+<ul>
+<li>The <a
+href="http://www.oracle.com/technetwork/java/javase/tzupdater-readme-136440.html">TZUpdater
+tool</a> compiles <code><abbr>tz</abbr></code> source into the format used by
+Oracle Java.</li>
+<li>The <a
+href="http://www.oracle.com/technetwork/articles/java/jf14-date-time-2125367.html">Java
+8 <code>java.time</code> <abbr>API</abbr></a> can be supplemented by <a
+href="http://www.threeten.org/threeten-extra/">ThreeTen-Extra</a>,
+which is freely available under a <abbr>BSD</abbr>-style license.</li>
+<li><a href="http://www.joda.org/joda-time/">Joda-Time &ndash; Java date
+and time <abbr>API</abbr></a> contains a class
+<code>org.joda.time.tz.ZoneInfoCompiler</code> that compiles
+<code><abbr>tz</abbr></code> source into a binary format. It inspired
+Java 8 <code>java.time</code>, which its users should migrate to once
+they can assume Java 8 or later. It is available under the <a
+href="https://www.apache.org/licenses/LICENSE-2.0">Apache License</a>.</li>
+<li><a href="https://github.com/MenoData/Time4J/">Time4J &ndash;
+Advanced date, time and interval library for Java</a> contains a class
+<code>net.time4j.tool.TimezoneRepositoryCompiler</code> that compiles
+<code><abbr>tz</abbr></code> source into a binary format. Time4J is
+available under the <a
+href="https://www.gnu.org/copyleft/lesser.html"><abbr>GNU</abbr> Lesser
+General Public License (<abbr title="Lesser General Public
+License">LGPL</abbr>)</a>.</li>
+<li><abbr>ICU</abbr> (mentioned <a href="#ICU">above</a>) contains compilers and
+Java-based libraries.</li>
+</ul>
+<li><a href="https://nodatime.org">Noda Time &ndash; Date and
+time <abbr>API</abbr> for .NET</a>
+and <a href="http://www.babiej.demon.nl/Tz4Net/main.htm">TZ4Net</a>
+are similar to Joda-Time and Time4J, but for the .NET framework instead of
+Java. They are freely available under the
+Apache License
+and a <abbr>BSD</abbr>-style license, respectively.</li>
+<li><a href="https://en.wikipedia.org/wiki/JavaScript">JavaScript</a>-based
+compilers and libraries include:
+<ul>
+<li><a
+href="https://github.com/kshetline/compact-time-zone-generator">CompactTimeZoneGenerator</a>
+compiles time zone data into a compact form designed for
+JavaScript. It is freely available under a combination of
+the <abbr>MIT</abbr> license and the Apache License.</li>
+<li><a href="https://momentjs.com/timezone/">Moment Timezone</a> is a
+plugin for the <a href="https://momentjs.com">Moment.js</a> date
+manipulation library. It is freely available under the <abbr>MIT</abbr>
+license.</li>
+<li><a href="https://github.com/mde/timezone-js">TimezoneJS.Date</a>'s
+<abbr>API</abbr> is upward compatible with standard JavaScript
+Dates. It is freely available under the Apache License.</li>
+<li><a href="https://github.com/sproutsocial/walltime-js">Walltime-js</a>
+translates <abbr>UT</abbr> to local time. It is freely available under
+the <abbr>MIT</abbr> license.</li>
+</ul>
+<li><a href="https://github.com/JuliaTime/">JuliaTime</a> contains a
+compiler from <code><abbr>tz</abbr></code> source into
+<a href="https://julialang.org/">Julia</a>. It is freely available
+under the <abbr>MIT</abbr> license.</li>
+<li><a href="http://pytz.sourceforge.net">pytz &ndash; World Timezone
+Definitions for Python</a> compiles <code><abbr>tz</abbr></code> source into
+<a href="https://www.python.org">Python</a>.
+It is freely available under a <abbr>BSD</abbr>-style license.</li>
+<li><a href="https://tzinfo.github.io">TZInfo &ndash;
+Ruby Timezone Library</a>
+compiles <code><abbr>tz</abbr></code> source into
+<a href="https://www.ruby-lang.org/en/">Ruby</a>.
+It is freely available under the <abbr>MIT</abbr> license.</li>
+<li>The <a href="http://www.squeaksource.com/Chronos/">Chronos Date/Time
+Library</a> is
+a <a href="https://en.wikipedia.org/wiki/Smalltalk">Smalltalk</a> class
+library that compiles <code><abbr>tz</abbr></code> source into a time
+zone repository whose format
+is either proprietary or an <abbr>XML</abbr>-encoded
+representation.</li>
+<li><a id="Tcl" href="https://tcl.tk">Tcl</a>
+contains a developer-oriented parser that compiles <code><abbr>tz</abbr></code>
+source into text files, along with a runtime that can read those
+files. Tcl is freely available under a <abbr>BSD</abbr>-style
+license.</li>
+</ul>
+<h2 id="binary">Other <code><abbr>tz</abbr></code> binary file readers</h2>
+<ul>
+<li>The <a
+href="https://www.gnu.org/software/libc/"><abbr>GNU</abbr> C
+Library</a>
+has an independent, thread-safe implementation of
+a <code><abbr>tz</abbr></code> binary file reader.
+This library is freely available under the LGPL
+and is widely used in <abbr>GNU</abbr>/Linux systems.</li>
+<li><a href="https://www.gnome.org">GNOME</a>'s
+<a href="https://developer.gnome.org/glib/">GLib</a> has
+a <code><abbr>tz</abbr></code> binary file reader written in C that
+creates a <code>GTimeZone</code> object representing sets
+of <abbr>UT</abbr> offsets.
+It is freely available under the <abbr>LGPL</abbr>.</li>
+<li>The
+<a href="https://github.com/bloomberg/bde/wiki">BDE Standard Library</a>'s
+<code>baltzo::TimeZoneUtil</code> component contains a C++
+implementation of a binary file reader. It is freely available under
+the Apache License.</li>
+<li><a href="https://github.com/google/cctz">CCTZ</a> is a simple C++
+library that translates between <abbr>UT</abbr> and civil time and
+can read binary files. It is freely available under the Apache
+License.</li>
+<li><a href="http://bmsi.com/java/#TZ">ZoneInfo.java</a>
+is a <code><abbr>tz</abbr></code> binary file reader written in Java.
+It is freely available under the <abbr>LGPL</abbr>.</li>
+<li><a href="https://github.com/derickr/timelib">Timelib</a> is a C
+library that reads tz binary files and converts
+time stamps from one time zone or format to another.
+It is used by <a href="https://secure.php.net"><abbr
+title="PHP: Hypertext Preprocessor">PHP</abbr></a>,
+<a href="https://hhvm.com"><abbr title="HipHop Virtual Machine">HHVM</abbr></a>,
+and <a href="https://www.mongodb.com">MongoDB</a>.
+It is freely available under the <abbr>MIT</abbr> license.</li>
+<li><a href="https://github.com/bigeasy/timezone">Timezone</a> is a
+JavaScript library that supports date arithmetic that is time zone
+aware. It is freely available under the <abbr>MIT</abbr> license.</li>
+<li>Tcl, mentioned <a href="#Tcl">above</a>, also contains a
+<code><abbr>tz</abbr></code> binary file reader.</li>
+<li><a href="http://search.cpan.org/perldoc?DateTime::TimeZone::Tzfile">
+DateTime::TimeZone::Tzfile</a>
+is a <code><abbr>tz</abbr></code> binary file reader written in Perl.
+It is freely available under the same terms as Perl
+(dual <abbr>GPL</abbr> and Artistic license).</li>
+<li>The
+public-domain <a href="https://github.com/dbaron/tz.js">tz.js</a>
+library contains a Python tool that
+converts <code><abbr>tz</abbr></code> binary data into
+<abbr>JSON</abbr>-format data suitable for use
+in its JavaScript library for time zone conversion. Dates before 1970
+are not supported.</li>
+<li>The <a
+href="https://hackage.haskell.org/package/timezone-olson">timezone-olson</a>
+package contains <a href="https://www.haskell.org">Haskell</a> code that
+parses and uses <code><abbr>tz</abbr></code> binary data. It is freely
+available under a <abbr>BSD</abbr>-style license.</li>
+</ul>
+<h2 id="software">Other <code><abbr>tz</abbr></code>-based time zone software</h2>
+<ul>
+<li><a href="https://foxclocks.org">FoxClocks</a>
+is an extension for <a href="https://www.google.com/chrome/">Google
+Chrome</a> and for <a
+href="https://developer.mozilla.org/en-US/docs/Mozilla/Tech/Toolkit_API">Mozilla
+Toolkit</a> applications like <a
+href="https://www.mozilla.org/en-US/firefox/new/">Firefox</a> and <a
+href="https://www.mozilla.org/en-US/thunderbird/">Thunderbird</a>.
+It displays multiple clocks in the application window, and has a mapping
+interface to <a href="https://www.google.com/earth/">Google Earth</a>.
+It is freely available under the <abbr>GPL</abbr>.</li>
+<li><a href="https://golang.org">Go programming language</a>
+implementations contain a copy of a 32-bit subset of a recent
+<code><abbr>tz</abbr></code> database in a
+Go-specific format.</li>
+<li><a
+href="http://users.skynet.be/Peter.Verthez/projects/intclock/">International
+clock (intclock)</a> is a clock that displays multiple time zones on
+<abbr>GNU</abbr>/Linux and similar systems. It is freely available
+under the <abbr>GPL</abbr>.</li>
+<li>Microsoft Windows 8.1
+and later has <code><abbr>tz</abbr></code> data and <abbr>CLDR</abbr>
+data (mentioned <a href="#CLDR">below</a>) used by
+<a href="https://en.wikipedia.org/wiki/Windows_Runtime">Windows Runtime</a>
+classes such as <a
+href="https://msdn.microsoft.com/en-us/library/windows/apps/windows.globalization.datetimeformatting.datetimeformatter.aspx"><code>DateTimeFormatter</code></a>.
+<a id="System.TimeZoneInfo"
+href="https://blogs.msdn.microsoft.com/bclteam/2007/06/07/exploring-windows-time-zones-with-system-timezoneinfo-josh-free/">Exploring
+Windows Time Zones with <code>System.TimeZoneInfo</code></a> describes
+the older, proprietary method of Microsoft Windows 2000 and later,
+which stores time zone data in the
+<a href="https://en.wikipedia.org/wiki/Windows_Registry">Windows Registry</a>. The
+<a
+href="https://unicode.org/cldr/charts/latest/supplemental/zone_tzid.html">Zone &rarr;
+Tzid table</a> or <a
+href="https://unicode.org/repos/cldr/trunk/common/supplemental/windowsZones.xml"><abbr>XML</abbr>
+file</a> of the <abbr>CLDR</abbr> data maps proprietary zone IDs
+to <code><abbr>tz</abbr></code> names.
+<li><a
+href="https://www.oracle.com/java/index.html">Oracle
+Java</a> contains a copy of a subset of a recent
+<code><abbr>tz</abbr></code> database in a
+Java-specific format.</li>
+<li><a href="https://www.relativedata.com/time-zone-master">Time Zone
+Master</a> is a Microsoft Windows clock program that can automatically
+download, compile and use <code>tz</code> releases. The Basic version
+is free.</li>
+<li><a
+href="http://veladg.com/velaterra.html">VelaTerra</a> is
+a macOS program. Its developers
+<a href="http://veladg.com/tzoffer.html">offer free
+licenses</a> to <code><abbr>tz</abbr></code> contributors.</li>
+</ul>
+<h2 id="other-dbs">Other time zone databases</h2>
+<ul>
+<li><a href="https://www.astro.com/atlas">Time-zone Atlas</a>
+is Astrodienst's Web version of Shanks and Pottenger's
+time zone history atlases also published in <a
+href="https://astrocom.com/astrology-products/software/acs-atlas-software">software</a>
+form by <a href="https://astrocom.com">ACS-Starcrafts</a>.
+These atlases are extensive but unreliable, as Shanks appears to have
+guessed many <abbr>UT</abbr> offsets and transitions. The atlases cite no
+sources and do not indicate which entries are guesswork.</li>
+<li><a href="https://en.wikipedia.org/wiki/HP-UX">HP-UX</a> has a database in
+its own <code>tztab</code>(4) format.</li>
+<li>Microsoft Windows has proprietary data mentioned
+<a href="#System.TimeZoneInfo">above</a>.</li>
+<li><a href="https://www.worldtimeserver.com">World Time Server</a>
+is another time zone database.</li>
+<li><a href="http://tycho.usno.navy.mil/tzones.html">World Time Zones</a>
+contains data from the Time Service Department of the
+<abbr>US</abbr> Naval Observatory.</li>
+<li>The <a
+href="https://www.iata.org/publications/store/Pages/standard-schedules-information.aspx">Standard
+Schedules Information Manual</a> of the
+International Air Transport Association
+gives current time zone rules for airports served by commercial aviation.</li>
+</ul>
+<h2 id="maps">Maps</h2>
+<ul>
+<li>The <a href="https://www.cia.gov/index.html">United States Central
+Intelligence Agency (<abbr
+title="Central Intelligence Agency">CIA</abbr>)</a> publishes a <a
+href="https://www.cia.gov/library/publications/the-world-factbook/graphics/ref_maps/physical/pdf/standard_time_zones_of_the_world.pdf">time
+zone map</a>; the
+<a
+href="https://www.lib.utexas.edu/maps/world.html">Perry&ndash;Casta&ntilde;eda
+Library Map Collection</a>
+of the University of Texas at Austin has copies of
+recent editions.
+The pictorial quality is good,
+but the maps do not indicate daylight saving time,
+and parts of the data are a few years out of date.</li>
+<li><a href="https://www.worldtimezone.com">Current time around the world
+and standard time zones map of the world</a>
+has several fancy time zone maps; it covers Russia particularly well.
+The maps' pictorial quality is not quite as good as the
+<abbr>CIA</abbr>'s
+but the maps are more up to date.</li>
+<li><a
+href="https://blog.poormansmath.net/how-much-is-time-wrong-around-the-world/">How
+much is time wrong around the world?</a> maps the difference between
+mean solar and standard time, highlighting areas such as western China
+where the two differ greatly. It's a bit out of date, unfortunately.</li>
+</ul>
+<h2 id="boundaries">Time zone boundaries</h2>
+<p>Geographical boundaries between time zone regions are available
+from several <a href="https://en.wikipedia.org/wiki/Geolocation">geolocation</a>
+services and other sources.</p>
+<ul>
+<li>Databases of time zone boundaries include:
+<ul>
+<li><a href="https://github.com/evansiroky/timezone-boundary-builder">Timezone
+Boundary Builder</a> extracts
+<a href="https://www.openstreetmap.org">Open Street Map</a> data to build
+boundaries of <code><abbr>tz</abbr></code> regions.
+Its code is freely available under the <abbr>MIT</abbr> license, and
+its data entries are freely available under the
+<a href="https://opendatacommons.org/licenses/odbl/">Open Data Commons
+Open Database License</a>. The maps' borders appear to be quite accurate.</li>
+<li><a href="http://efele.net/maps/tz/"><abbr>TZ</abbr> timezones
+maps</a> contains <a
+href="https://en.wikipedia.org/wiki/Shapefile">shapefiles</a> of
+sets of <code><abbr>tz</abbr></code> regions. This includes
+<a href="http://efele.net/maps/tz/world/">tz_world</a>, a shapefile
+for all the world's regions. These maps are no longer maintained and
+are superseded by the Timezone Boundary Builder.</li>
+<li><a
+href="https://github.com/straup/whereonearth-timezone">Whereonearth-timezone</a>
+is in <a href="https://tools.ietf.org/html/rfc7946">GeoJSON</a> format
+(Internet <abbr>RFC</abbr> 7946), and combines the
+the tz_world shapefiles with the
+<a href="https://developer.yahoo.com/geo/geoplanet/">GeoPlanet</a>
+dataset.</li>
+</ul></li>
+<li>Programmatic interfaces that map geographical coordinates via tz_world to
+<code><abbr>tz</abbr></code> regions include:
+<ul>
+<li><a href="https://github.com/mj1856/GeoTimeZone">GeoTimeZone</a> is
+written in <a
+href="https://en.wikipedia.org/wiki/C_Sharp_(programming_language)">C#</a>
+and is freely available under the <abbr>MIT</abbr> license.</li>
+<li>The <a href="https://github.com/bradfitz/latlong">latlong package</a>
+is written in Go and is freely available under the Apache License.</li>
+<li><a href="https://github.com/drtimcooper/LatLongToTimezone">LatLongToTimezone</a>,
+in both Java and
+<a href="https://en.wikipedia.org/wiki/Swift_(programming_language)">Swift</a>
+form, is freely available under the MIT license.</li>
+<li>For <a href="https://nodejs.org/en/">Node.js</a>,
+the <a href="https://www.npmjs.com/package/geo-tz">geo-tz module</a>
+is freely available under the MIT license, and
+the <a href="https://www.npmjs.com/package/tz-lookup">tz-lookup module</a>
+is in the public domain.</li>
+<li>The <a
+href="https://github.com/MrMinimal64/timezonefinder">timezonefinder</a>
+library for Python is freely available under the MIT license.
+<li>The <a
+href="https://github.com/gunyarakun/timezone_finder">timezone_finder</a>
+library for Ruby is freely available under the MIT license.</li>
+<li><a href="https://derickrethans.nl/what-time-is-it.html">What Time
+is It Here?</a> applies MongoDB
+geospatial query operators to shapefiles' data.</li>
+</ul></li>
+<li>Free access via a network API, if you register a key, is provided by
+the <a href="http://www.geonames.org/export/web-services.html#timezone">GeoNames Timezone web service</a>,
+the <a href="https://developers.google.com/maps/documentation/timezone/intro">Google Maps Time Zone API</a>, and
+the <a href="https://timezonedb.com">Time Zone Database &amp; API</a>.
+Commercial network API access is provided
+by <a href="https://askgeo.com">AskGeo</a>
+and <a href="https://www.geogarage.com/blog/news-1/post/geogarage-time-zone-api-31">GeoGarage</a>.
+</li>
+<li>"<a
+href="https://stackoverflow.com/questions/16086962/how-to-get-a-time-zone-from-a-location-using-latitude-and-longitude-coordinates/16086964">How
+to get a time zone from a location using latitude and longitude
+coordinates?</a>" discusses other geolocation possibilities.</li>
+<li><a href="http://statoids.com/statoids.html">Administrative
+Divisions of Countries ("Statoids")</a> lists
+political subdivision data related to time zones.</li>
+<li><a href="http://home.kpn.nl/vanadovv/time/Multizones.html">Time
+zone boundaries for multizone countries</a> summarizes legal
+boundaries between time zones within countries.</li>
+<li><a href="http://manifold.net/info/freestuff.shtml">Manifold Software
+&ndash; GIS and Database Tools</a> includes a Manifold-format map of
+world time zone boundaries distributed under the
+<abbr>GPL</abbr>.</li>
+<li>A ship within the <a
+href="https://en.wikipedia.org/wiki/Territorial_waters">territorial
+waters</a> of any nation uses that nation's time. In international
+waters, time zone boundaries are meridians 15&deg; apart, except that
+<abbr>UT</abbr>&minus;12 and <abbr>UT</abbr>+12 are each 7.5&deg;
+wide and are separated by
+the 180&deg; meridian (not by the International Date Line, which is
+for land and territorial waters only). A captain can change ship's
+clocks any time after entering a new time zone; midnight changes are
+common.</li>
+</ul>
+<h2 id="civil">Civil time concepts and history</h2>
+<ul>
+<li><a href="https://www.nist.gov/pml/time-and-frequency-division/popular-links/walk-through-time">A
+Walk through Time</a>
+surveys the evolution of timekeeping.</li>
+<li><a href="http://www.webexhibits.org/daylightsaving/">About Daylight
+Saving Time &ndash; History, rationale, laws &amp; dates</a>
+is an overall history of <abbr>DST</abbr>.</li>
+<li><a href="https://www.w3.org/TR/timezone/">Working with Time Zones</a>
+contains guidelines and best practices for software applications that
+deal with civil time.</li>
+<li><a href="http://seizethedaylight.com/dst/">A Brief
+History of Daylight Saving Time</a> summarizes some of the contentious
+history of <abbr>DST</abbr>.</li>
+<li><a href="https://www.staff.science.uu.nl/~gent0113/idl/idl.htm">A History of
+the International Date Line</a> tells the story of the most important
+time zone boundary.</li>
+<li><a href="http://statoids.com/tconcept.html">Basic Time
+Zone Concepts</a> discusses terminological issues behind time zones.</li>
+</ul>
+<h2 id="national">National histories of legal time</h2>
+<dl>
+<dt>Australia</dt>
+<dd>The Parliamentary Library has commissioned a <a
+href="https://www.aph.gov.au/binaries/library/pubs/rp/2009-10/10rp10.pdf">research
+paper on daylight saving time in Australia</a>.
+The Bureau of Meteorology publishes a list of <a
+href="http://www.bom.gov.au/climate/averages/tables/dst_times.shtml">Implementation
+Dates of Daylight Savings Time within Australia</a>.</dd>
+<dt>Belgium</dt>
+<dd>The Royal Observatory of Belgium maintains a table of <a
+href="http://www.astro.oma.be/GENERAL/INFO/nli001a.html"
+hreflang="nl">time in Belgium (in Dutch)</a>.</dd>
+<dt>Brazil</dt>
+<dd>The Time Service Department of the National Observatory
+records <a href="http://pcdsh01.on.br/DecHV.html"
+hreflang="pt-BR">Brazil's daylight saving time decrees (in
+Portuguese)</a>.</dd>
+<dt>Canada</dt>
+<dd>National Research Council Canada publishes current
+and some older information about <a
+href="https://www.nrc-cnrc.gc.ca/eng/services/time/time_zones.html">time
+zones &amp; daylight saving time</a>.</dd>
+<dt>Chile</dt>
+<dd>The Hydrographic and Oceanographic Service of the Chilean Navy publishes a
+<a href="http://www.horaoficial.cl/historia_hora.html" hreflang="es">history of
+Chile's official time (in Spanish)</a>.</dd>
+<dt>Czech Republic</dt>
+<dd><a href="https://kalendar.beda.cz/kdy-zacina-a-konci-letni-cas"
+hreflang="cs">When daylight saving time starts and ends (in Czech)</a>
+summarizes and cites historical DST regulations.</dd>
+<dt>Germany</dt>
+<dd>The National Institute for Science and Technology maintains the <a
+href="https://www.ptb.de/cms/en/fachabteilungen/abt4/fb-44/ag-441/realisation-of-legal-time-in-germany.html">Realisation
+of Legal Time in Germany</a>.</dd>
+<dt>Israel</dt>
+<dd>The Interior Ministry periodically issues <a
+href="ftp://ftp.cs.huji.ac.il/pub/tz/announcements"
+hreflang="he">announcements (in Hebrew)</a>.</dd>
+<dt>Italy</dt>
+<dd>The National Institute of Metrological Research maintains a
+<a href="http://www.nanospin.eu/res/tf/ora_legale_i.shtml">table of civil time
+(in Italian)</a>.</dd>
+<dt>Mexico</dt>
+<dd>The Investigation and Analysis Service of the Mexican Library of
+Congress has published a <a
+href="http://www.diputados.gob.mx/bibliot/publica/inveyana/polisoc/horver/index.htm"
+hreflang="es">history of Mexican local time (in Spanish)</a>.</dd>
+<dt>Malaysia</dt>
+<dd>See Singapore <a href="#Singapore">below</a>.</dd>
+<dt>Netherlands</dt>
+<dd><a href="https://www.staff.science.uu.nl/~gent0113/wettijd/wettijd.htm"
+hreflang="nl">Legal time in the Netherlands (in Dutch)</a>
+covers the history of local time in the Netherlands from ancient times.</dd>
+<dt>New Zealand</dt>
+<dd>The Department of Internal Affairs maintains a brief <a
+href="https://www.dia.govt.nz/Daylight-Saving-History">History of
+Daylight Saving</a>. The privately-maintained <a
+href="http://astrologyschool.com/nztime.html">History of New Zealand
+time</a> has more details.</dd>
+<dt>Singapore</dt>
+<dd><a id="Singapore"
+href="http://www.math.nus.edu.sg/aslaksen/teaching/timezone.html">Why
+is Singapore in the "Wrong" Time Zone?</a> details the
+history of legal time in Singapore and Malaysia.</dd>
+<dt>United Kingdom</dt>
+<dd><a
+href="https://www.polyomino.org.uk/british-time/">History of
+legal time in Britain</a> discusses in detail the country
+with perhaps the best-documented history of clock adjustments.
+The National Physical Laboratory also maintains an <a
+href="http://www.npl.co.uk/educate-explore/what-is-time/archive-of-summer-time-dates">Archive
+of Summer time dates</a>.</dd>
+<dt>United States</dt>
+<dd>The Department of Transportation's <a
+href="https://www.transportation.gov/regulations/recent-time-zone-proceedings">Recent
+Time Zone Proceedings</a> lists changes to time zone boundaries.</dd>
+<dt>Uruguay</dt>
+<dd>The Oceanography, Hydrography, and Meteorology Service of the Uruguayan
+Navy (SOHMA) publishes an annual <a
+href="http://www.armada.mil.uy/Pagina/institucion/dimat/sohma/almanaque.html" hreflang="es">almanac
+(in Spanish)</a>.</dd>
+</dl>
+<h2 id="precision">Precision timekeeping</h2>
+<ul>
+<li><a
+href="http://leapsecond.com/hpan/an1289.pdf">The
+Science of Timekeeping</a> is a thorough introduction
+to the theory and practice of precision timekeeping.</li>
+<li><a href="https://doi.org/10.1007/978-3-319-59909-0">The Science of
+Time 2016</a> contains several freely-readable papers.</li>
+<li><a href="http://www.ntp.org"><abbr
+title="Network Time Protocol">NTP</abbr>: The Network
+Time Protocol</a> (Internet <abbr>RFC</abbr> 5905)
+discusses how to synchronize clocks of
+Internet hosts.</li>
+<li>The <a
+href="https://www.nist.gov/intelligent-systems-division/ieee-1588">Precision
+Time Protocol</a> (<abbr
+title="Institute of Electrical and Electronics Engineers">IEEE</abbr> 1588)
+can achieve submicrosecond clock accuracy on a local area network.</li>
+<li><a
+href="https://tools.ietf.org/html/rfc4833">Timezone
+Options for <abbr title="Dynamic Host Configuration Protocol">DHCP</abbr></a>
+(Internet <abbr>RFC</abbr> 4833)
+specifies a <a
+href="https://en.wikipedia.org/wiki/Dynamic_Host_Configuration_Protocol"><abbr>DHCP</abbr></a>
+option for a server to configure
+a client's time zone and daylight saving settings automatically.</li>
+<li><a
+href="https://www.cv.nrao.edu/~rfisher/Ephemerides/times.html">Astronomical
+Times</a> explains more abstruse astronomical time scales like
+<abbr title="Terrestrial Dynamic Time">TDT</abbr>,
+<abbr title="Geocentric Coordinate Time">TCG</abbr>, and
+<abbr title="Barycentric Dynamic Time">TDB</abbr>.
+<a href="https://www.ucolick.org/~sla/leapsecs/timescales.html">Time
+Scales</a> goes into more detail, particularly for historical variants.</li>
+<li>The <a href="https://www.iau.org"><abbr
+title="International Astronomical Union">IAU</abbr></a>'s <a
+href="http://www.iausofa.org"><abbr
+title="Standards Of Fundamental Astronomy">SOFA</abbr></a>
+collection contains C and <a
+href="https://en.wikipedia.org/wiki/Fortran">Fortran</a>
+code for converting among time scales like
+<abbr title="International Atomic Time">TAI</abbr>,
+<abbr>TDB</abbr>, <abbr>TDT</abbr> and
+<abbr>UTC</abbr>.</li>
+<li><a
+href="https://www.giss.nasa.gov/tools/mars24/help/notes.html">Mars24 Sunclock
+&ndash; Time on Mars</a> describes Airy Mean Time (<abbr>AMT</abbr>) and the
+diverse local time
+scales used by each landed mission on Mars.</li>
+<li><a href="http://leapsecond.com">LeapSecond.com</a> is
+dedicated not only to leap seconds but to precise time and frequency
+in general. It covers the state of the art in amateur timekeeping, and
+how the art has progressed over the past few decades.</li>
+<li><a
+href="https://www.iers.org/IERS/EN/Publications/Bulletins/bulletins.html"><abbr
+title="International Earth Rotation and Reference Systems Service">IERS</abbr>
+Bulletins</a> contains official publications of the International
+Earth Rotation and Reference Systems Service, which decides when leap
+seconds occur. The <code>tz</code> code and data support leap seconds
+via an optional "<code>right</code>" configuration, as opposed to the
+default "<code>posix</code>" configuration.</li>
+<li><a href="https://developers.google.com/time/smear">Leap Smear</a>
+discusses how to gradually adjust <abbr>POSIX</abbr> clocks near a
+leap second so that they disagree with <abbr>UTC</abbr> by at most a
+half second, even though every <abbr>POSIX</abbr> minute has exactly
+sixty seconds. This approach works with the default <code>tz</code>
+"<code>posix</code>" configuration, is <a
+href="http://bk1.ntp.org/ntp-stable/README.leapsmear">supported</a> by
+the <abbr>NTP</abbr> reference implementation, and is used by major
+cloud service providers.</li>
+<li>The <a
+href="https://pairlist6.pair.net/mailman/listinfo/leapsecs">Leap
+Second Discussion List</a> covers <a
+href="https://www2.unb.ca/gge/Resources/gpsworld.november99.pdf">McCarthy
+and Klepczynski's 1999 proposal to discontinue leap seconds</a>,
+discussed further in
+<a href="https://www.cl.cam.ac.uk/~mgk25/time/metrologia-leapsecond.pdf">The
+leap second: its history and possible future</a>.
+<a href="https://www.ucolick.org/~sla/leapsecs/"><abbr>UTC</abbr>
+might be redefined
+without Leap Seconds</a> gives pointers on this
+contentious issue, which was active until 2015 and could become active
+again.</li>
+</ul>
+<h2 id="notation">Time notation</h2>
+<ul>
+<li>The <a id="CLDR" href="http://cldr.unicode.org">Unicode Common Locale Data
+Repository (<abbr>CLDR</abbr>) Project</a> has localizations for time
+zone names, abbreviations, identifiers, and formats. For example, it
+contains French translations for "Eastern European Summer Time",
+"<abbr title="Eastern European Summer Time">EEST</abbr>", and
+"Bucharest". Its
+<a href="https://unicode.org/cldr/charts/latest/by_type/">by-type
+charts</a> show these values for many locales. Data values are available in
+both <abbr title="Locale Data Markup Language">LDML</abbr>
+(an <abbr>XML</abbr> format) and <abbr>JSON</abbr>.
+<li>
+<a href="https://www.cl.cam.ac.uk/~mgk25/iso-time.html">A summary of
+the international standard date and time notation</a> is a good
+summary of
+<a
+href="https://www.iso.org/standard/40874.html"><em><abbr>ISO</abbr>
+8601:2004 &ndash; Data elements and interchange formats &ndash; Information
+interchange &ndash; Representation of dates and times</em></a>.</li>
+<li>
+<a href="https://www.w3.org/TR/xmlschema-2/#dateTime"><abbr>XML</abbr>
+Schema: Datatypes &ndash; dateTime</a> specifies a format inspired by
+<abbr>ISO</abbr> 8601 that is in common use in <abbr>XML</abbr> data.</li>
+<li><a href="https://tools.ietf.org/html/rfc5322#section-3.3">&sect;3.3 of
+Internet Message Format</a> (Internet <abbr>RFC</abbr> 5322)
+specifies the time notation used in email and <a
+href="https://en.wikipedia.org/wiki/Hypertext_Transfer_Protocol"><abbr>HTTP</abbr></a>
+headers.</li>
+<li>
+<a href="https://tools.ietf.org/html/rfc3339">Date and Time
+on the Internet: Timestamps</a> (Internet <abbr>RFC</abbr> 3339)
+specifies an <abbr>ISO</abbr> 8601
+profile for use in new Internet
+protocols.</li>
+<li>
+<a href="https://www.hackcraft.net/web/datetime/">Date &amp; Time
+Formats on the Web</a> surveys web- and Internet-oriented date and time
+formats.</li>
+<li>Alphabetic time zone abbreviations should not be used as unique
+identifiers for <abbr>UT</abbr> offsets as they are ambiguous in
+practice. For example, in English-speaking North America
+"<abbr>CST</abbr>" denotes 6 hours behind <abbr>UT</abbr>,
+but in China it denotes 8 hours ahead of <abbr>UT</abbr>,
+and French-speaking North Americans prefer
+"<abbr title="Heure Normale du Centre">HNC</abbr>" to
+"<abbr>CST</abbr>". The <code><abbr>tz</abbr></code>
+database contains English abbreviations for many time stamps;
+unfortunately some of these abbreviations were merely the database maintainers'
+inventions, and these have been removed when possible.</li>
+<li>Numeric time zone abbreviations typically count hours east of
+<abbr>UT</abbr>, e.g., +09 for Japan and
+&minus;10 for Hawaii. However, the <abbr>POSIX</abbr>
+<code><abbr>TZ</abbr></code> environment variable uses the opposite convention.
+For example, one might use <code><abbr>TZ</abbr>="<abbr
+title="Japan Standard Time">JST</abbr>-9"</code> and
+<code><abbr>TZ</abbr>="<abbr title="Hawaii Standard Time">HST</abbr>10"</code>
+for Japan and Hawaii, respectively. If the
+<code><abbr>tz</abbr></code> database is available, it is usually better to use
+settings like <code><abbr>TZ</abbr>="Asia/Tokyo"</code> and
+<code><abbr>TZ</abbr>="Pacific/Honolulu"</code> instead, as this should avoid
+confusion, handle old time stamps better, and insulate you better from
+any future changes to the rules. One should never set
+<abbr>POSIX</abbr> <code><abbr>TZ</abbr></code> to a value like
+<code>"GMT-9"</code>, though, since this would incorrectly imply that
+local time is nine hours ahead of <abbr>UT</abbr> and the time zone
+is called "<abbr>GMT</abbr>".</li>
+</ul>
+<h2 id="see-also">See also</h2>
+<ul>
+<li><a href="theory.html">Theory and pragmatics of the tz code and data</a></li>
+<li><a href="tz-art.html">Time and the Arts</a></li>
+</ul>
+<hr>
+<address>
+This web page is in the public domain, so clarified as of
+2009-05-17 by Arthur David Olson.
+<br>
+Please send corrections to this web page to the
+<a href="mailto:tz@iana.org">time zone mailing list</a>.
+</address>
+</body>
+</html>
diff --git a/tzfile.5 b/tzfile.5
new file mode 100644
index 000000000000..530397f72e67
--- /dev/null
+++ b/tzfile.5
@@ -0,0 +1,190 @@
+.TH TZFILE 5
+.SH NAME
+tzfile \- time zone information
+.SH DESCRIPTION
+.ie '\(lq'' .ds lq \&"\"
+.el .ds lq \(lq\"
+.ie '\(rq'' .ds rq \&"\"
+.el .ds rq \(rq\"
+.de q
+\\$3\*(lq\\$1\*(rq\\$2
+..
+The time zone information files used by
+.BR tzset (3)
+are typically found under a directory with a name like
+.IR /usr/share/zoneinfo .
+These files begin with a 44-byte header containing the following fields:
+.IP * 2
+The magic four-byte ASCII sequence
+.q "TZif"
+identifies the file as a time zone information file.
+.IP *
+A byte identifying the version of the file's format
+(as of 2017, either an ASCII NUL, or
+.q "2",
+or
+.q "3" ).
+.IP *
+Fifteen bytes containing zeros reserved for future use.
+.IP *
+Six four-byte integer values
+written in a standard byte order
+(the high-order byte of the value is written first).
+These values are,
+in order:
+.RS
+.TP
+.I tzh_ttisgmtcnt
+The number of UT/local indicators stored in the file.
+.TP
+.I tzh_ttisstdcnt
+The number of standard/wall indicators stored in the file.
+.TP
+.I tzh_leapcnt
+The number of leap seconds for which data entries are stored in the file.
+.TP
+.I tzh_timecnt
+The number of transition times for which data entries are stored
+in the file.
+.TP
+.I tzh_typecnt
+The number of local time types for which data entries are stored
+in the file (must not be zero).
+.TP
+.I tzh_charcnt
+The number of bytes of time zone abbreviation strings
+stored in the file.
+.RE
+.PP
+The above header is followed by the following fields, whose lengths
+depend on the contents of the header:
+.IP * 2
+.I tzh_timecnt
+four-byte signed integer values sorted in ascending order.
+These values are written in standard byte order.
+Each is used as a transition time (as returned by
+.BR time (2))
+at which the rules for computing local time change.
+.IP *
+.I tzh_timecnt
+one-byte unsigned integer values;
+each one tells which of the different types of local time types
+described in the file is associated with the time period
+starting with the same-indexed transition time.
+These values serve as indices into the next field.
+.IP *
+.I tzh_typecnt
+.I ttinfo
+entries, each defined as follows:
+.in +.5i
+.sp
+.nf
+.ta .5i +\w'unsigned char\0\0'u
+struct ttinfo {
+	int32_t	tt_gmtoff;
+	unsigned char	tt_isdst;
+	unsigned char	tt_abbrind;
+};
+.in -.5i
+.fi
+.sp
+Each structure is written as a four-byte signed integer value for
+.IR tt_gmtoff ,
+in a standard byte order, followed by a one-byte value for
+.I tt_isdst
+and a one-byte value for
+.IR tt_abbrind .
+In each structure,
+.I tt_gmtoff
+gives the number of seconds to be added to UT,
+.I tt_isdst
+tells whether
+.I tm_isdst
+should be set by
+.BR localtime (3)
+and
+.I tt_abbrind
+serves as an index into the array of time zone abbreviation bytes
+that follow the
+.I ttinfo
+structure(s) in the file.
+.IP *
+.I tzh_leapcnt
+pairs of four-byte values, written in standard byte order;
+the first value of each pair gives the nonnegative time
+(as returned by
+.BR time (2))
+at which a leap second occurs;
+the second gives the
+.I total
+number of leap seconds to be applied during the time period
+starting at the given time.
+The pairs of values are sorted in ascending order by time.
+Each transition is for one leap second, either positive or negative;
+transitions always separated by at least 28 days minus 1 second.
+.IP *
+.I tzh_ttisstdcnt
+standard/wall indicators, each stored as a one-byte value;
+they tell whether the transition times associated with local time types
+were specified as standard time or wall clock time,
+and are used when a time zone file is used in handling POSIX-style
+time zone environment variables.
+.IP *
+.I tzh_ttisgmtcnt
+UT/local indicators, each stored as a one-byte value;
+they tell whether the transition times associated with local time types
+were specified as UT or local time,
+and are used when a time zone file is used in handling POSIX-style
+time zone environment variables.
+.PP
+The
+.BR localtime (3)
+function
+uses the first standard-time
+.I ttinfo
+structure in the file
+(or simply the first
+.I ttinfo
+structure in the absence of a standard-time structure)
+if either
+.I tzh_timecnt
+is zero or the time argument is less than the first transition time recorded
+in the file.
+.SS Version 2 format
+For version-2-format time zone files,
+the above header and data are followed by a second header and data,
+identical in format except that
+eight bytes are used for each transition time or leap second time.
+(Leap second counts remain four bytes.)
+After the second header and data comes a newline-enclosed,
+POSIX-TZ-environment-variable-style string for use in handling instants
+after the last transition time stored in the file
+(with nothing between the newlines if there is no POSIX representation for
+such instants).
+The POSIX-style string must agree with the local time type after
+both data's last transition times; for example, given the string
+.q "WET0WEST,M3.5.0,M10.5.0/3"
+then if a last transition time is in July, the transition's local time
+type must specify a daylight-saving time abbreviated
+.q "WEST"
+that is one hour east of UT.
+.SS Version 3 format
+For version-3-format time zone files, the POSIX-TZ-style string may
+use two minor extensions to the POSIX TZ format, as described in
+.BR newtzset (3).
+First, the hours part of its transition times may be signed and range from
+\*-167 through 167 instead of the POSIX-required unsigned values
+from 0 through 24.  Second, DST is in effect all year if it starts
+January 1 at 00:00 and ends December 31 at 24:00 plus the difference
+between daylight saving and standard time.
+.PP
+Future changes to the format may append more data.
+.SH SEE ALSO
+.BR time (2),
+.BR localtime (3),
+.BR tzset (3),
+.BR tzselect (8),
+.BR zdump (8),
+.BR zic (8)
+.\" This file is in the public domain, so clarified as of
+.\" 1996-06-05 by Arthur David Olson.
diff --git a/tzfile.5.txt b/tzfile.5.txt
new file mode 100644
index 000000000000..d55ac47fcb27
--- /dev/null
+++ b/tzfile.5.txt
@@ -0,0 +1,129 @@
+TZFILE(5)                     File Formats Manual                    TZFILE(5)
+
+NAME
+       tzfile - time zone information
+
+DESCRIPTION
+       The time zone information files used by tzset(3) are typically found
+       under a directory with a name like /usr/share/zoneinfo.  These files
+       begin with a 44-byte header containing the following fields:
+
+       * The magic four-byte ASCII sequence "TZif" identifies the file as a
+         time zone information file.
+
+       * A byte identifying the version of the file's format (as of 2017,
+         either an ASCII NUL, or "2", or "3").
+
+       * Fifteen bytes containing zeros reserved for future use.
+
+       * Six four-byte integer values written in a standard byte order (the
+         high-order byte of the value is written first).  These values are, in
+         order:
+
+         tzh_ttisgmtcnt
+                The number of UT/local indicators stored in the file.
+
+         tzh_ttisstdcnt
+                The number of standard/wall indicators stored in the file.
+
+         tzh_leapcnt
+                The number of leap seconds for which data entries are stored
+                in the file.
+
+         tzh_timecnt
+                The number of transition times for which data entries are
+                stored in the file.
+
+         tzh_typecnt
+                The number of local time types for which data entries are
+                stored in the file (must not be zero).
+
+         tzh_charcnt
+                The number of bytes of time zone abbreviation strings stored
+                in the file.
+
+       The above header is followed by the following fields, whose lengths
+       depend on the contents of the header:
+
+       * tzh_timecnt four-byte signed integer values sorted in ascending
+         order.  These values are written in standard byte order.  Each is
+         used as a transition time (as returned by time(2)) at which the rules
+         for computing local time change.
+
+       * tzh_timecnt one-byte unsigned integer values; each one tells which of
+         the different types of local time types described in the file is
+         associated with the time period starting with the same-indexed
+         transition time.  These values serve as indices into the next field.
+
+       * tzh_typecnt ttinfo entries, each defined as follows:
+
+              struct ttinfo {
+                   int32_t        tt_gmtoff;
+                   unsigned char  tt_isdst;
+                   unsigned char  tt_abbrind;
+              };
+
+         Each structure is written as a four-byte signed integer value for
+         tt_gmtoff, in a standard byte order, followed by a one-byte value for
+         tt_isdst and a one-byte value for tt_abbrind.  In each structure,
+         tt_gmtoff gives the number of seconds to be added to UT, tt_isdst
+         tells whether tm_isdst should be set by localtime(3) and tt_abbrind
+         serves as an index into the array of time zone abbreviation bytes
+         that follow the ttinfo structure(s) in the file.
+
+       * tzh_leapcnt pairs of four-byte values, written in standard byte
+         order; the first value of each pair gives the nonnegative time (as
+         returned by time(2)) at which a leap second occurs; the second gives
+         the total number of leap seconds to be applied during the time period
+         starting at the given time.  The pairs of values are sorted in
+         ascending order by time.  Each transition is for one leap second,
+         either positive or negative; transitions always separated by at least
+         28 days minus 1 second.
+
+       * tzh_ttisstdcnt standard/wall indicators, each stored as a one-byte
+         value; they tell whether the transition times associated with local
+         time types were specified as standard time or wall clock time, and
+         are used when a time zone file is used in handling POSIX-style time
+         zone environment variables.
+
+       * tzh_ttisgmtcnt UT/local indicators, each stored as a one-byte value;
+         they tell whether the transition times associated with local time
+         types were specified as UT or local time, and are used when a time
+         zone file is used in handling POSIX-style time zone environment
+         variables.
+
+       The localtime(3) function uses the first standard-time ttinfo structure
+       in the file (or simply the first ttinfo structure in the absence of a
+       standard-time structure) if either tzh_timecnt is zero or the time
+       argument is less than the first transition time recorded in the file.
+
+   Version 2 format
+       For version-2-format time zone files, the above header and data are
+       followed by a second header and data, identical in format except that
+       eight bytes are used for each transition time or leap second time.
+       (Leap second counts remain four bytes.)  After the second header and
+       data comes a newline-enclosed, POSIX-TZ-environment-variable-style
+       string for use in handling instants after the last transition time
+       stored in the file (with nothing between the newlines if there is no
+       POSIX representation for such instants).  The POSIX-style string must
+       agree with the local time type after both data's last transition times;
+       for example, given the string "WET0WEST,M3.5.0,M10.5.0/3" then if a
+       last transition time is in July, the transition's local time type must
+       specify a daylight-saving time abbreviated "WEST" that is one hour east
+       of UT.
+
+   Version 3 format
+       For version-3-format time zone files, the POSIX-TZ-style string may use
+       two minor extensions to the POSIX TZ format, as described in
+       newtzset(3).  First, the hours part of its transition times may be
+       signed and range from 167 through 167 instead of the POSIX-required
+       unsigned values from 0 through 24.  Second, DST is in effect all year
+       if it starts January 1 at 00:00 and ends December 31 at 24:00 plus the
+       difference between daylight saving and standard time.
+
+       Future changes to the format may append more data.
+
+SEE ALSO
+       time(2), localtime(3), tzset(3), tzselect(8), zdump(8), zic(8)
+
+                                                                     TZFILE(5)
diff --git a/tzfile.h b/tzfile.h
new file mode 100644
index 000000000000..f7f5cafd33bf
--- /dev/null
+++ b/tzfile.h
@@ -0,0 +1,117 @@
+#ifndef TZFILE_H
+
+#define TZFILE_H
+
+/*
+** This file is in the public domain, so clarified as of
+** 1996-06-05 by Arthur David Olson.
+*/
+
+/*
+** This header is for use ONLY with the time conversion code.
+** There is no guarantee that it will remain unchanged,
+** or that it will remain at all.
+** Do NOT copy it to any system include directory.
+** Thank you!
+*/
+
+/*
+** Information about time zone files.
+*/
+
+#ifndef TZDIR
+#define TZDIR	"/usr/share/zoneinfo" /* Time zone object file directory */
+#endif /* !defined TZDIR */
+
+#ifndef TZDEFAULT
+#define TZDEFAULT	"/etc/localtime"
+#endif /* !defined TZDEFAULT */
+
+#ifndef TZDEFRULES
+#define TZDEFRULES	"posixrules"
+#endif /* !defined TZDEFRULES */
+
+/*
+** Each file begins with. . .
+*/
+
+#define	TZ_MAGIC	"TZif"
+
+struct tzhead {
+	char	tzh_magic[4];		/* TZ_MAGIC */
+	char	tzh_version[1];		/* '\0' or '2' or '3' as of 2013 */
+	char	tzh_reserved[15];	/* reserved; must be zero */
+	char	tzh_ttisgmtcnt[4];	/* coded number of trans. time flags */
+	char	tzh_ttisstdcnt[4];	/* coded number of trans. time flags */
+	char	tzh_leapcnt[4];		/* coded number of leap seconds */
+	char	tzh_timecnt[4];		/* coded number of transition times */
+	char	tzh_typecnt[4];		/* coded number of local time types */
+	char	tzh_charcnt[4];		/* coded number of abbr. chars */
+};
+
+/*
+** . . .followed by. . .
+**
+**	tzh_timecnt (char [4])s		coded transition times a la time(2)
+**	tzh_timecnt (unsigned char)s	types of local time starting at above
+**	tzh_typecnt repetitions of
+**		one (char [4])		coded UT offset in seconds
+**		one (unsigned char)	used to set tm_isdst
+**		one (unsigned char)	that's an abbreviation list index
+**	tzh_charcnt (char)s		'\0'-terminated zone abbreviations
+**	tzh_leapcnt repetitions of
+**		one (char [4])		coded leap second transition times
+**		one (char [4])		total correction after above
+**	tzh_ttisstdcnt (char)s		indexed by type; if 1, transition
+**					time is standard time, if 0,
+**					transition time is wall clock time
+**					if absent, transition times are
+**					assumed to be wall clock time
+**	tzh_ttisgmtcnt (char)s		indexed by type; if 1, transition
+**					time is UT, if 0,
+**					transition time is local time
+**					if absent, transition times are
+**					assumed to be local time
+*/
+
+/*
+** If tzh_version is '2' or greater, the above is followed by a second instance
+** of tzhead and a second instance of the data in which each coded transition
+** time uses 8 rather than 4 chars,
+** then a POSIX-TZ-environment-variable-style string for use in handling
+** instants after the last transition time stored in the file
+** (with nothing between the newlines if there is no POSIX representation for
+** such instants).
+**
+** If tz_version is '3' or greater, the above is extended as follows.
+** First, the POSIX TZ string's hour offset may range from -167
+** through 167 as compared to the POSIX-required 0 through 24.
+** Second, its DST start time may be January 1 at 00:00 and its stop
+** time December 31 at 24:00 plus the difference between DST and
+** standard time, indicating DST all year.
+*/
+
+/*
+** In the current implementation, "tzset()" refuses to deal with files that
+** exceed any of the limits below.
+*/
+
+#ifndef TZ_MAX_TIMES
+#define TZ_MAX_TIMES	2000
+#endif /* !defined TZ_MAX_TIMES */
+
+#ifndef TZ_MAX_TYPES
+/* This must be at least 17 for Europe/Samara and Europe/Vilnius.  */
+#define TZ_MAX_TYPES	256 /* Limited by what (unsigned char)'s can hold */
+#endif /* !defined TZ_MAX_TYPES */
+
+#ifndef TZ_MAX_CHARS
+#define TZ_MAX_CHARS	50	/* Maximum number of abbreviation characters */
+				/* (limited by what unsigned chars can hold) */
+#endif /* !defined TZ_MAX_CHARS */
+
+#ifndef TZ_MAX_LEAPS
+#define TZ_MAX_LEAPS	50	/* Maximum number of leap second corrections */
+#endif /* !defined TZ_MAX_LEAPS */
+
+#endif /* !defined TZFILE_H */
diff --git a/tzselect.8 b/tzselect.8
new file mode 100644
index 000000000000..847d6dd45e88
--- /dev/null
+++ b/tzselect.8
@@ -0,0 +1,113 @@
+.TH TZSELECT 8
+.SH NAME
+tzselect \- select a time zone
+.SH SYNOPSIS
+.ie \n(.g .ds - \f(CW-\fP
+.el ds - \-
+.B tzselect
+[
+.B \*-c
+.I coord
+] [
+.B \*-n
+.I limit
+] [
+.B \*-\*-help
+] [
+.B \*-\*-version
+]
+.SH DESCRIPTION
+The
+.B tzselect
+program asks the user for information about the current location,
+and outputs the resulting time zone description to standard output.
+The output is suitable as a value for the TZ environment variable.
+.PP
+All interaction with the user is done via standard input and standard error.
+.SH OPTIONS
+.TP
+.BI "\*-c " coord
+Instead of asking for continent and then country and then city,
+ask for selection from time zones whose largest cities
+are closest to the location with geographical coordinates
+.I coord.
+Use ISO 6709 notation for
+.I coord,
+that is, a latitude immediately followed by a longitude.  The latitude
+and longitude should be signed integers followed by an optional
+decimal point and fraction: positive numbers represent north and east,
+negative south and west.  Latitudes with two and longitudes with three
+integer digits are treated as degrees; latitudes with four or six and
+longitudes with five or seven integer digits are treated as
+.I "DDMM, DDDMM, DDMMSS,"
+or
+.I DDDMMSS
+representing
+.I DD
+or
+.I DDD
+degrees,
+.I MM
+minutes,
+and zero or
+.I SS
+seconds, with any trailing fractions represent fractional minutes or
+(if
+.I SS
+is present) seconds.  The decimal point is that of the current locale.
+For example, in the (default) C locale,
+.B "\*-c\ +40.689\*-074.045"
+specifies 40.689\(de\|N, 74.045\(de\|W,
+.B "\*-c\ +4041.4\*-07402.7"
+specifies 40\(de\|41.4\(fm\|N, 74\(de\|2.7\(fm\|W, and
+.B "\*-c\ +404121\*-0740240"
+specifies 40\(de\|41\(fm\|21\(sd\|N, 74\(de\|2\(fm\|40\(sd\|W.
+If
+.I coord
+is not one of the documented forms, the resulting behavior is unspecified.
+.TP
+.BI "\*-n " limit
+When
+.B \*-c
+is used, display the closest
+.I limit
+locations (default 10).
+.TP
+.B "\*-\*-help"
+Output help information and exit.
+.TP
+.B "\*-\*-version"
+Output version information and exit.
+.SH "ENVIRONMENT VARIABLES"
+.TP
+\f3AWK\fP
+Name of a Posix-compliant
+.I awk
+program (default:
+.BR awk ).
+.TP
+\f3TZDIR\fP
+Name of the directory containing time zone data files (default:
+.BR /usr/share/zoneinfo ).
+.SH FILES
+.TP
+\f2TZDIR\fP\f3/iso3166.tab\fP
+Table of ISO 3166 2-letter country codes and country names.
+.TP
+\f2TZDIR\fP\f3/zone1970.tab\fP
+Table of country codes, latitude and longitude, zone names, and
+descriptive comments.
+.TP
+\f2TZDIR\fP\f3/\fP\f2TZ\fP
+Time zone data file for time zone \f2TZ\fP.
+.SH "EXIT STATUS"
+The exit status is zero if a time zone was successfully obtained from the user,
+nonzero otherwise.
+.SH "SEE ALSO"
+newctime(3), tzfile(5), zdump(8), zic(8)
+.SH NOTES
+Applications should not assume that
+.BR tzselect 's
+output matches the user's political preferences.
+.\" This file is in the public domain, so clarified as of
+.\" 2009-05-17 by Arthur David Olson.
diff --git a/tzselect.8.txt b/tzselect.8.txt
new file mode 100644
index 000000000000..991475087bdc
--- /dev/null
+++ b/tzselect.8.txt
@@ -0,0 +1,77 @@
+TZSELECT(8)                 System Manager's Manual                TZSELECT(8)
+
+NAME
+       tzselect - select a time zone
+
+SYNOPSIS
+       tzselect [ -c coord ] [ -n limit ] [ --help ] [ --version ]
+
+DESCRIPTION
+       The tzselect program asks the user for information about the current
+       location, and outputs the resulting time zone description to standard
+       output.  The output is suitable as a value for the TZ environment
+       variable.
+
+       All interaction with the user is done via standard input and standard
+       error.
+
+OPTIONS
+       -c coord
+              Instead of asking for continent and then country and then city,
+              ask for selection from time zones whose largest cities are
+              closest to the location with geographical coordinates coord.
+              Use ISO 6709 notation for coord, that is, a latitude immediately
+              followed by a longitude.  The latitude and longitude should be
+              signed integers followed by an optional decimal point and
+              fraction: positive numbers represent north and east, negative
+              south and west.  Latitudes with two and longitudes with three
+              integer digits are treated as degrees; latitudes with four or
+              six and longitudes with five or seven integer digits are treated
+              as DDMM, DDDMM, DDMMSS, or DDDMMSS representing DD or DDD
+              degrees, MM minutes, and zero or SS seconds, with any trailing
+              fractions represent fractional minutes or (if SS is present)
+              seconds.  The decimal point is that of the current locale.  For
+              example, in the (default) C locale, -c +40.689-074.045 specifies
+              40.689oN, 74.045oW, -c +4041.4-07402.7 specifies 40o41.4'N,
+              74o2.7'W, and -c +404121-0740240 specifies 40o41'21''N,
+              74o2'40''W.  If coord is not one of the documented forms, the
+              resulting behavior is unspecified.
+
+       -n limit
+              When -c is used, display the closest limit locations (default
+              10).
+
+       --help Output help information and exit.
+
+       --version
+              Output version information and exit.
+
+ENVIRONMENT VARIABLES
+       AWK    Name of a Posix-compliant awk program (default: awk).
+
+       TZDIR  Name of the directory containing time zone data files (default:
+              /usr/share/zoneinfo).
+
+FILES
+       TZDIR/iso3166.tab
+              Table of ISO 3166 2-letter country codes and country names.
+
+       TZDIR/zone1970.tab
+              Table of country codes, latitude and longitude, zone names, and
+              descriptive comments.
+
+       TZDIR/TZ
+              Time zone data file for time zone TZ.
+
+EXIT STATUS
+       The exit status is zero if a time zone was successfully obtained from
+       the user, nonzero otherwise.
+
+SEE ALSO
+       newctime(3), tzfile(5), zdump(8), zic(8)
+
+NOTES
+       Applications should not assume that tzselect's output matches the
+       user's political preferences.
+
+                                                                   TZSELECT(8)
diff --git a/tzselect.ksh b/tzselect.ksh
new file mode 100644
index 000000000000..cde80d1be940
--- /dev/null
+++ b/tzselect.ksh
@@ -0,0 +1,561 @@
+#!/bin/bash
+
+PKGVERSION='(tzcode) '
+TZVERSION=see_Makefile
+REPORT_BUGS_TO=tz@iana.org
+
+# Ask the user about the time zone, and output the resulting TZ value to stdout.
+# Interact with the user via stderr and stdin.
+
+# Contributed by Paul Eggert.  This file is in the public domain.
+
+# Porting notes:
+#
+# This script requires a Posix-like shell and prefers the extension of a
+# 'select' statement.  The 'select' statement was introduced in the
+# Korn shell and is available in Bash and other shell implementations.
+# If your host lacks both Bash and the Korn shell, you can get their
+# source from one of these locations:
+#
+#	Bash <https://www.gnu.org/software/bash/>
+#	Korn Shell <http://www.kornshell.com/>
+#	MirBSD Korn Shell <https://www.mirbsd.org/mksh.htm>
+#
+# For portability to Solaris 9 /bin/sh this script avoids some POSIX
+# features and common extensions, such as $(...) (which works sometimes
+# but not others), $((...)), and $10.
+#
+# This script also uses several features of modern awk programs.
+# If your host lacks awk, or has an old awk that does not conform to Posix,
+# you can use either of the following free programs instead:
+#
+#	Gawk (GNU awk) <https://www.gnu.org/software/gawk/>
+#	mawk <https://invisible-island.net/mawk/>
+
+
+# Specify default values for environment variables if they are unset.
+: ${AWK=awk}
+: ${TZDIR=`pwd`}
+
+# Output one argument as-is to standard output.
+# Safer than 'echo', which can mishandle '\' or leading '-'.
+say() {
+    printf '%s\n' "$1"
+}
+
+# Check for awk Posix compliance.
+($AWK -v x=y 'BEGIN { exit 123 }') </dev/null >/dev/null 2>&1
+[ $? = 123 ] || {
+	say >&2 "$0: Sorry, your '$AWK' program is not Posix compatible."
+	exit 1
+}
+
+coord=
+location_limit=10
+zonetabtype=zone1970
+
+usage="Usage: tzselect [--version] [--help] [-c COORD] [-n LIMIT]
+Select a time zone interactively.
+
+Options:
+
+  -c COORD
+    Instead of asking for continent and then country and then city,
+    ask for selection from time zones whose largest cities
+    are closest to the location with geographical coordinates COORD.
+    COORD should use ISO 6709 notation, for example, '-c +4852+00220'
+    for Paris (in degrees and minutes, North and East), or
+    '-c -35-058' for Buenos Aires (in degrees, South and West).
+
+  -n LIMIT
+    Display at most LIMIT locations when -c is used (default $location_limit).
+
+  --version
+    Output version information.
+
+  --help
+    Output this help.
+
+Report bugs to $REPORT_BUGS_TO."
+
+# Ask the user to select from the function's arguments,
+# and assign the selected argument to the variable 'select_result'.
+# Exit on EOF or I/O error.  Use the shell's 'select' builtin if available,
+# falling back on a less-nice but portable substitute otherwise.
+if
+  case $BASH_VERSION in
+  ?*) : ;;
+  '')
+    # '; exit' should be redundant, but Dash doesn't properly fail without it.
+    (eval 'set --; select x; do break; done; exit') </dev/null 2>/dev/null
+  esac
+then
+  # Do this inside 'eval', as otherwise the shell might exit when parsing it
+  # even though it is never executed.
+  eval '
+    doselect() {
+      select select_result
+      do
+	case $select_result in
+	"") echo >&2 "Please enter a number in range." ;;
+	?*) break
+	esac
+      done || exit
+    }
+
+    # Work around a bug in bash 1.14.7 and earlier, where $PS3 is sent to stdout.
+    case $BASH_VERSION in
+    [01].*)
+      case `echo 1 | (select x in x; do break; done) 2>/dev/null` in
+      ?*) PS3=
+      esac
+    esac
+  '
+else
+  doselect() {
+    # Field width of the prompt numbers.
+    select_width=`expr $# : '.*'`
+
+    select_i=
+
+    while :
+    do
+      case $select_i in
+      '')
+	select_i=0
+	for select_word
+	do
+	  select_i=`expr $select_i + 1`
+	  printf >&2 "%${select_width}d) %s\\n" $select_i "$select_word"
+	done ;;
+      *[!0-9]*)
+	echo >&2 'Please enter a number in range.' ;;
+      *)
+	if test 1 -le $select_i && test $select_i -le $#; then
+	  shift `expr $select_i - 1`
+	  select_result=$1
+	  break
+	fi
+	echo >&2 'Please enter a number in range.'
+      esac
+
+      # Prompt and read input.
+      printf >&2 %s "${PS3-#? }"
+      read select_i || exit
+    done
+  }
+fi
+
+while getopts c:n:t:-: opt
+do
+    case $opt$OPTARG in
+    c*)
+	coord=$OPTARG ;;
+    n*)
+	location_limit=$OPTARG ;;
+    t*) # Undocumented option, used for developer testing.
+	zonetabtype=$OPTARG ;;
+    -help)
+	exec echo "$usage" ;;
+    -version)
+	exec echo "tzselect $PKGVERSION$TZVERSION" ;;
+    -*)
+	say >&2 "$0: -$opt$OPTARG: unknown option; try '$0 --help'"; exit 1 ;;
+    *)
+	say >&2 "$0: try '$0 --help'"; exit 1 ;;
+    esac
+done
+
+shift `expr $OPTIND - 1`
+case $# in
+0) ;;
+*) say >&2 "$0: $1: unknown argument"; exit 1 ;;
+esac
+
+# Make sure the tables are readable.
+TZ_COUNTRY_TABLE=$TZDIR/iso3166.tab
+TZ_ZONE_TABLE=$TZDIR/$zonetabtype.tab
+for f in $TZ_COUNTRY_TABLE $TZ_ZONE_TABLE
+do
+	<"$f" || {
+		say >&2 "$0: time zone files are not set up correctly"
+		exit 1
+	}
+done
+
+# If the current locale does not support UTF-8, convert data to current
+# locale's format if possible, as the shell aligns columns better that way.
+# Check the UTF-8 of U+12345 CUNEIFORM SIGN URU TIMES KI.
+! $AWK 'BEGIN { u12345 = "\360\222\215\205"; exit length(u12345) != 1 }' &&
+    { tmp=`(mktemp -d) 2>/dev/null` || {
+	tmp=${TMPDIR-/tmp}/tzselect.$$ &&
+	(umask 77 && mkdir -- "$tmp")
+    };} &&
+    trap 'status=$?; rm -fr -- "$tmp"; exit $status' 0 HUP INT PIPE TERM &&
+    (iconv -f UTF-8 -t //TRANSLIT <"$TZ_COUNTRY_TABLE" >$tmp/iso3166.tab) \
+        2>/dev/null &&
+    TZ_COUNTRY_TABLE=$tmp/iso3166.tab &&
+    iconv -f UTF-8 -t //TRANSLIT <"$TZ_ZONE_TABLE" >$tmp/$zonetabtype.tab &&
+    TZ_ZONE_TABLE=$tmp/$zonetabtype.tab
+
+newline='
+'
+IFS=$newline
+
+
+# Awk script to read a time zone table and output the same table,
+# with each column preceded by its distance from 'here'.
+output_distances='
+  BEGIN {
+    FS = "\t"
+    while (getline <TZ_COUNTRY_TABLE)
+      if ($0 ~ /^[^#]/)
+        country[$1] = $2
+    country["US"] = "US" # Otherwise the strings get too long.
+  }
+  function abs(x) {
+    return x < 0 ? -x : x;
+  }
+  function min(x, y) {
+    return x < y ? x : y;
+  }
+  function convert_coord(coord, deg, minute, ilen, sign, sec) {
+    if (coord ~ /^[-+]?[0-9]?[0-9][0-9][0-9][0-9][0-9][0-9]([^0-9]|$)/) {
+      degminsec = coord
+      intdeg = degminsec < 0 ? -int(-degminsec / 10000) : int(degminsec / 10000)
+      minsec = degminsec - intdeg * 10000
+      intmin = minsec < 0 ? -int(-minsec / 100) : int(minsec / 100)
+      sec = minsec - intmin * 100
+      deg = (intdeg * 3600 + intmin * 60 + sec) / 3600
+    } else if (coord ~ /^[-+]?[0-9]?[0-9][0-9][0-9][0-9]([^0-9]|$)/) {
+      degmin = coord
+      intdeg = degmin < 0 ? -int(-degmin / 100) : int(degmin / 100)
+      minute = degmin - intdeg * 100
+      deg = (intdeg * 60 + minute) / 60
+    } else
+      deg = coord
+    return deg * 0.017453292519943296
+  }
+  function convert_latitude(coord) {
+    match(coord, /..*[-+]/)
+    return convert_coord(substr(coord, 1, RLENGTH - 1))
+  }
+  function convert_longitude(coord) {
+    match(coord, /..*[-+]/)
+    return convert_coord(substr(coord, RLENGTH))
+  }
+  # Great-circle distance between points with given latitude and longitude.
+  # Inputs and output are in radians.  This uses the great-circle special
+  # case of the Vicenty formula for distances on ellipsoids.
+  function gcdist(lat1, long1, lat2, long2, dlong, x, y, num, denom) {
+    dlong = long2 - long1
+    x = cos(lat2) * sin(dlong)
+    y = cos(lat1) * sin(lat2) - sin(lat1) * cos(lat2) * cos(dlong)
+    num = sqrt(x * x + y * y)
+    denom = sin(lat1) * sin(lat2) + cos(lat1) * cos(lat2) * cos(dlong)
+    return atan2(num, denom)
+  }
+  # Parallel distance between points with given latitude and longitude.
+  # This is the product of the longitude difference and the cosine
+  # of the latitude of the point that is further from the equator.
+  # I.e., it considers longitudes to be further apart if they are
+  # nearer the equator.
+  function pardist(lat1, long1, lat2, long2) {
+    return abs(long1 - long2) * min(cos(lat1), cos(lat2))
+  }
+  # The distance function is the sum of the great-circle distance and
+  # the parallel distance.  It could be weighted.
+  function dist(lat1, long1, lat2, long2) {
+    return gcdist(lat1, long1, lat2, long2) + pardist(lat1, long1, lat2, long2)
+  }
+  BEGIN {
+    coord_lat = convert_latitude(coord)
+    coord_long = convert_longitude(coord)
+  }
+  /^[^#]/ {
+    here_lat = convert_latitude($2)
+    here_long = convert_longitude($2)
+    line = $1 "\t" $2 "\t" $3
+    sep = "\t"
+    ncc = split($1, cc, /,/)
+    for (i = 1; i <= ncc; i++) {
+      line = line sep country[cc[i]]
+      sep = ", "
+    }
+    if (NF == 4)
+      line = line " - " $4
+    printf "%g\t%s\n", dist(coord_lat, coord_long, here_lat, here_long), line
+  }
+'
+
+# Begin the main loop.  We come back here if the user wants to retry.
+while
+
+	echo >&2 'Please identify a location' \
+		'so that time zone rules can be set correctly.'
+
+	continent=
+	country=
+	region=
+
+	case $coord in
+	?*)
+		continent=coord;;
+	'')
+
+	# Ask the user for continent or ocean.
+
+	echo >&2 'Please select a continent, ocean, "coord", or "TZ".'
+
+        quoted_continents=`
+	  $AWK '
+	    BEGIN { FS = "\t" }
+	    /^[^#]/ {
+              entry = substr($3, 1, index($3, "/") - 1)
+              if (entry == "America")
+		entry = entry "s"
+              if (entry ~ /^(Arctic|Atlantic|Indian|Pacific)$/)
+		entry = entry " Ocean"
+              printf "'\''%s'\''\n", entry
+            }
+          ' <"$TZ_ZONE_TABLE" |
+	  sort -u |
+	  tr '\n' ' '
+	  echo ''
+	`
+
+	eval '
+	    doselect '"$quoted_continents"' \
+		"coord - I want to use geographical coordinates." \
+		"TZ - I want to specify the time zone using the Posix TZ format."
+	    continent=$select_result
+	    case $continent in
+	    Americas) continent=America;;
+	    *" "*) continent=`expr "$continent" : '\''\([^ ]*\)'\''`
+	    esac
+	'
+	esac
+
+	case $continent in
+	TZ)
+		# Ask the user for a Posix TZ string.  Check that it conforms.
+		while
+			echo >&2 'Please enter the desired value' \
+				'of the TZ environment variable.'
+			echo >&2 'For example, AEST-10 is a zone named AEST' \
+				'that is 10 hours'
+			echo >&2 'ahead (east) of Greenwich,' \
+				'with no daylight saving time.'
+			read TZ
+			$AWK -v TZ="$TZ" 'BEGIN {
+				tzname = "(<[[:alnum:]+-]{3,}>|[[:alpha:]]{3,})"
+				time = "(2[0-4]|[0-1]?[0-9])" \
+				  "(:[0-5][0-9](:[0-5][0-9])?)?"
+				offset = "[-+]?" time
+				mdate = "M([1-9]|1[0-2])\\.[1-5]\\.[0-6]"
+				jdate = "((J[1-9]|[0-9]|J?[1-9][0-9]" \
+				  "|J?[1-2][0-9][0-9])|J?3[0-5][0-9]|J?36[0-5])"
+				datetime = ",(" mdate "|" jdate ")(/" time ")?"
+				tzpattern = "^(:.*|" tzname offset "(" tzname \
+				  "(" offset ")?(" datetime datetime ")?)?)$"
+				if (TZ ~ tzpattern) exit 1
+				exit 0
+			}'
+		do
+		    say >&2 "'$TZ' is not a conforming Posix time zone string."
+		done
+		TZ_for_date=$TZ;;
+	*)
+		case $continent in
+		coord)
+		    case $coord in
+		    '')
+			echo >&2 'Please enter coordinates' \
+				'in ISO 6709 notation.'
+			echo >&2 'For example, +4042-07403 stands for'
+			echo >&2 '40 degrees 42 minutes north,' \
+				'74 degrees 3 minutes west.'
+			read coord;;
+		    esac
+		    distance_table=`$AWK \
+			    -v coord="$coord" \
+			    -v TZ_COUNTRY_TABLE="$TZ_COUNTRY_TABLE" \
+			    "$output_distances" <"$TZ_ZONE_TABLE" |
+		      sort -n |
+		      sed "${location_limit}q"
+		    `
+		    regions=`say "$distance_table" | $AWK '
+		      BEGIN { FS = "\t" }
+		      { print $NF }
+		    '`
+		    echo >&2 'Please select one of the following' \
+			    'time zone regions,'
+		    echo >&2 'listed roughly in increasing order' \
+			    "of distance from $coord".
+		    doselect $regions
+		    region=$select_result
+		    TZ=`say "$distance_table" | $AWK -v region="$region" '
+		      BEGIN { FS="\t" }
+		      $NF == region { print $4 }
+		    '`
+		    ;;
+		*)
+		# Get list of names of countries in the continent or ocean.
+		countries=`$AWK \
+			-v continent="$continent" \
+			-v TZ_COUNTRY_TABLE="$TZ_COUNTRY_TABLE" \
+		'
+			BEGIN { FS = "\t" }
+			/^#/ { next }
+			$3 ~ ("^" continent "/") {
+			    ncc = split($1, cc, /,/)
+			    for (i = 1; i <= ncc; i++)
+				if (!cc_seen[cc[i]]++) cc_list[++ccs] = cc[i]
+			}
+			END {
+				while (getline <TZ_COUNTRY_TABLE) {
+					if ($0 !~ /^#/) cc_name[$1] = $2
+				}
+				for (i = 1; i <= ccs; i++) {
+					country = cc_list[i]
+					if (cc_name[country]) {
+					  country = cc_name[country]
+					}
+					print country
+				}
+			}
+		' <"$TZ_ZONE_TABLE" | sort -f`
+
+
+		# If there's more than one country, ask the user which one.
+		case $countries in
+		*"$newline"*)
+			echo >&2 'Please select a country' \
+				'whose clocks agree with yours.'
+			doselect $countries
+			country=$select_result;;
+		*)
+			country=$countries
+		esac
+
+
+		# Get list of names of time zone rule regions in the country.
+		regions=`$AWK \
+			-v country="$country" \
+			-v TZ_COUNTRY_TABLE="$TZ_COUNTRY_TABLE" \
+		'
+			BEGIN {
+				FS = "\t"
+				cc = country
+				while (getline <TZ_COUNTRY_TABLE) {
+					if ($0 !~ /^#/  &&  country == $2) {
+						cc = $1
+						break
+					}
+				}
+			}
+			/^#/ { next }
+			$1 ~ cc { print $4 }
+		' <"$TZ_ZONE_TABLE"`
+
+
+		# If there's more than one region, ask the user which one.
+		case $regions in
+		*"$newline"*)
+			echo >&2 'Please select one of the following' \
+				'time zone regions.'
+			doselect $regions
+			region=$select_result;;
+		*)
+			region=$regions
+		esac
+
+		# Determine TZ from country and region.
+		TZ=`$AWK \
+			-v country="$country" \
+			-v region="$region" \
+			-v TZ_COUNTRY_TABLE="$TZ_COUNTRY_TABLE" \
+		'
+			BEGIN {
+				FS = "\t"
+				cc = country
+				while (getline <TZ_COUNTRY_TABLE) {
+					if ($0 !~ /^#/  &&  country == $2) {
+						cc = $1
+						break
+					}
+				}
+			}
+			/^#/ { next }
+			$1 ~ cc && $4 == region { print $3 }
+		' <"$TZ_ZONE_TABLE"`
+		esac
+
+		# Make sure the corresponding zoneinfo file exists.
+		TZ_for_date=$TZDIR/$TZ
+		<"$TZ_for_date" || {
+			say >&2 "$0: time zone files are not set up correctly"
+			exit 1
+		}
+	esac
+
+
+	# Use the proposed TZ to output the current date relative to UTC.
+	# Loop until they agree in seconds.
+	# Give up after 8 unsuccessful tries.
+
+	extra_info=
+	for i in 1 2 3 4 5 6 7 8
+	do
+		TZdate=`LANG=C TZ="$TZ_for_date" date`
+		UTdate=`LANG=C TZ=UTC0 date`
+		TZsec=`expr "$TZdate" : '.*:\([0-5][0-9]\)'`
+		UTsec=`expr "$UTdate" : '.*:\([0-5][0-9]\)'`
+		case $TZsec in
+		$UTsec)
+			extra_info="
+Selected time is now:	$TZdate.
+Universal Time is now:	$UTdate."
+			break
+		esac
+	done
+
+
+	# Output TZ info and ask the user to confirm.
+
+	echo >&2 ""
+	echo >&2 "The following information has been given:"
+	echo >&2 ""
+	case $country%$region%$coord in
+	?*%?*%)	say >&2 "	$country$newline	$region";;
+	?*%%)	say >&2 "	$country";;
+	%?*%?*) say >&2 "	coord $coord$newline	$region";;
+	%%?*)	say >&2 "	coord $coord";;
+	*)	say >&2 "	TZ='$TZ'"
+	esac
+	say >&2 ""
+	say >&2 "Therefore TZ='$TZ' will be used.$extra_info"
+	say >&2 "Is the above information OK?"
+
+	doselect Yes No
+	ok=$select_result
+	case $ok in
+	Yes) break
+	esac
+do coord=
+done
+
+case $SHELL in
+*csh) file=.login line="setenv TZ '$TZ'";;
+*) file=.profile line="TZ='$TZ'; export TZ"
+esac
+
+test -t 1 && say >&2 "
+You can make this change permanent for yourself by appending the line
+	$line
+to the file '$file' in your home directory; then log out and log in again.
+
+Here is that TZ value again, this time on standard output so that you
+can use the $0 command in shell scripts:"
+
+say "$TZ"
diff --git a/version b/version
new file mode 100644
index 000000000000..cc61cea271c9
--- /dev/null
+++ b/version
@@ -0,0 +1 @@
+2018e
diff --git a/workman.sh b/workman.sh
new file mode 100755
index 000000000000..4b3b64ae078e
--- /dev/null
+++ b/workman.sh
@@ -0,0 +1,32 @@
+#! /bin/sh
+
+# This file is in the public domain, so clarified as of
+# 2009-05-17 by Arthur David Olson.
+
+# Tell groff not to emit SGR escape sequences (ANSI color escapes).
+GROFF_NO_SGR=1
+export GROFF_NO_SGR
+
+echo ".am TH
+.hy 0
+.na
+..
+.rm }H
+.rm }F" | nroff -man - ${1+"$@"} | perl -ne '
+	binmode STDIN, '\'':encoding(utf8)'\'';
+	binmode STDOUT, '\'':encoding(utf8)'\'';
+	chomp;
+	s/.\010//g;
+	s/\s*$//;
+	if (/^$/) {
+		$sawblank = 1;
+		next;
+	} else {
+		if ($sawblank && $didprint) {
+			print "\n";
+			$sawblank = 0;
+		}
+		print "$_\n";
+		$didprint = 1;
+	}
+'
diff --git a/zdump.8 b/zdump.8
new file mode 100644
index 000000000000..ef611db7cf9e
--- /dev/null
+++ b/zdump.8
@@ -0,0 +1,226 @@
+.TH ZDUMP 8
+.SH NAME
+zdump \- time zone dumper
+.SH SYNOPSIS
+.B zdump
+[
+.I option
+\&... ] [
+.I zonename
+\&... ]
+.SH DESCRIPTION
+.ie '\(lq'' .ds lq \&"\"
+.el .ds lq \(lq\"
+.ie '\(rq'' .ds rq \&"\"
+.el .ds rq \(rq\"
+.de q
+\\$3\*(lq\\$1\*(rq\\$2
+..
+.ie \n(.g .ds - \f(CW-\fP
+.el ds - \-
+.I Zdump
+prints the current time in each
+.I zonename
+named on the command line.
+.PP
+These options are available:
+.TP
+.BI "\*-\*-version"
+Output version information and exit.
+.TP
+.B \*-i
+.I "(This option is experimental: its behavior may change in future versions.)"
+Output a description of time intervals.  For each
+.I zonename
+on the command line, output an interval-format description of the
+zone.  See
+.q "INTERVAL FORMAT"
+below.
+.TP
+.B \*-v
+Output a verbose description of time intervals.
+For each
+.I zonename
+on the command line,
+print the time at the lowest possible time value,
+the time one day after the lowest possible time value,
+the times both one second before and exactly at
+each detected time discontinuity,
+the time at one day less than the highest possible time value,
+and the time at the highest possible time value.
+Each line is followed by
+.BI isdst= D
+where
+.I D
+is positive, zero, or negative depending on whether
+the given time is daylight saving time, standard time,
+or an unknown time type, respectively.
+Each line is also followed by
+.BI gmtoff= N
+if the given local time is known to be
+.I N
+seconds east of Greenwich.
+.TP
+.B \*-V
+Like
+.BR \*-v ,
+except omit the times relative to the extreme time values.
+This generates output that is easier to compare to that of
+implementations with different time representations.
+.TP
+.BI "\*-c " [loyear,]hiyear
+Cut off interval output at the given year(s).
+Cutoff times are computed using the proleptic Gregorian calendar with year 0
+and with Universal Time (UT) ignoring leap seconds.
+The lower bound is exclusive and the upper is inclusive; for example, a
+.I loyear
+of 1970 excludes a transition occurring at 1970-01-01 00:00:00 UTC but a
+.I hiyear
+of 1970 includes the transition.
+The default cutoff is
+.BR \*-500,2500 .
+.TP
+.BI "\*-t " [lotime,]hitime
+Cut off interval output at the given time(s),
+given in decimal seconds since 1970-01-01 00:00:00
+Coordinated Universal Time (UTC).
+The
+.I zonename
+determines whether the count includes leap seconds.
+As with
+.BR \*-c ,
+the cutoff's lower bound is exclusive and its upper bound is inclusive.
+.SH "INTERVAL FORMAT"
+.I "This format is experimental: it may change in future versions."
+.PP
+The interval format is a compact text representation that is intended
+to be both human- and machine-readable.  It consists of an empty line,
+then a line
+.q "TZ=\fIstring\fP"
+where
+.I string
+is a double-quoted string giving the zone name, a second line
+.q "\*- \*- \fIinterval\fP"
+describing the time interval before the first transition if any, and
+zero or more following lines
+.q "\fIdate time interval\fP",
+one line for each transition time and following interval.  Fields are
+separated by single tabs.
+.PP
+Dates are in
+.IR yyyy - mm - dd
+format and times are in 24-hour
+.IR hh : mm : ss
+format where
+.IR hh <24.
+Times are in local time immediately after the transition.  A
+time interval description consists of a UT offset in signed
+.RI \(+- hhmmss
+format, a time zone abbreviation, and an isdst flag.  An abbreviation
+that equals the UT offset is omitted; other abbreviations are
+double-quoted strings unless they consist of one or more alphabetic
+characters.  An isdst flag is omitted for standard time, and otherwise
+is a decimal integer that is unsigned and positive (typically 1) for
+daylight saving time and negative for unknown.
+.PP
+In times and in UT offsets with absolute value less than 100 hours,
+the seconds are omitted if they are zero, and
+the minutes are also omitted if they are also zero.  Positive UT
+offsets are east of Greenwich.  The UT offset \*-00 denotes a UT
+placeholder in areas where the actual offset is unspecified; by
+convention, this occurs when the UT offset is zero and the time zone
+abbreviation begins with
+.q "\*-"
+or is
+.q "zzz".
+.PP
+In double-quoted strings, escape sequences represent unusual
+characters.  The escape sequences are \es for space, and \e", \e\e,
+\ef, \en, \er, \et, and \ev with their usual meaning in the C
+programming language.  E.g., the double-quoted string
+\*(lq"CET\es\e"\e\e"\*(rq represents the character sequence \*(lqCET
+"\e\*(rq.\""
+.PP
+.ne 9
+Here is an example of the output, with the leading empty line omitted.
+(This example is shown with tab stops set far enough apart so that the
+tabbed columns line up.)
+.nf
+.sp
+.if \n(.g .ft CW
+.if t .in +.5i
+.if n .in +2
+.nr w \w'1896-01-13 'u
+.ta \nwu +\nwu +\nwu +\nwu
+TZ="Pacific/Honolulu"
+-	-	-10:31:26	LMT
+1896-01-13	12:01:26	-10:30	HST
+1933-04-30	03	-09:30	HDT	1
+1933-05-21	11	-10:30	HST
+1942-02-09	03	-09:30	HDT	1
+1945-09-30	01	-10:30	HST
+1947-06-08	02:30	-10	HST
+.in
+.if \n(.g .ft
+.sp
+.fi
+Here, local time begins 10 hours, 31 minutes and 26 seconds west of
+UT, and is a standard time abbreviated LMT.  Immediately after the
+first transition, the date is 1896-01-13 and the time is 12:01:26, and
+the following time interval is 10.5 hours west of UT, a standard time
+abbreviated HST.  Immediately after the second transition, the date is
+1933-04-30 and the time is 03:00:00 and the following time interval is
+9.5 hours west of UT, is abbreviated HDT, and is daylight saving time.
+Immediately after the last transition the date is 1947-06-08 and the
+time is 02:30:00, and the following time interval is 10 hours west of
+UT, a standard time abbreviated HST.
+.PP
+.ne 10
+Here are excerpts from another example:
+.nf
+.sp
+.if \n(.g .ft CW
+.if t .in +.5i
+.if n .in +2
+TZ="Europe/Astrakhan"
+-	-	+03:12:12	LMT
+1924-04-30	23:47:48	+03
+1930-06-21	01	+04
+1981-04-01	01	+05		1
+1981-09-30	23	+04
+\&...
+2014-10-26	01	+03
+2016-03-27	03	+04
+.in
+.if \n(.g .ft
+.sp
+.fi
+This time zone is east of UT, so its UT offsets are positive.  Also,
+many of its time zone abbreviations are omitted since they duplicate
+the text of the UT offset.
+.SH LIMITATIONS
+Time discontinuities are found by sampling the results returned by localtime
+at twelve-hour intervals.
+This works in all real-world cases;
+one can construct artificial time zones for which this fails.
+.PP
+In the
+.B \*-v
+and
+.B \*-V
+output,
+.q "UT"
+denotes the value returned by
+.IR gmtime (3),
+which uses UTC for modern time stamps and some other UT flavor for
+time stamps that predate the introduction of UTC.
+No attempt is currently made to have the output use
+.q "UTC"
+for newer and
+.q "UT"
+for older time stamps, partly because the exact date of the
+introduction of UTC is problematic.
+.SH "SEE ALSO"
+newctime(3), tzfile(5), zic(8)
+.\" This file is in the public domain, so clarified as of
+.\" 2009-05-17 by Arthur David Olson.
diff --git a/zdump.8.txt b/zdump.8.txt
new file mode 100644
index 000000000000..a24d652deac3
--- /dev/null
+++ b/zdump.8.txt
@@ -0,0 +1,144 @@
+ZDUMP(8)                    System Manager's Manual                   ZDUMP(8)
+
+NAME
+       zdump - time zone dumper
+
+SYNOPSIS
+       zdump [ option ... ] [ zonename ... ]
+
+DESCRIPTION
+       Zdump prints the current time in each zonename named on the command
+       line.
+
+       These options are available:
+
+       --version
+              Output version information and exit.
+
+       -i     (This option is experimental: its behavior may change in future
+              versions.)  Output a description of time intervals.  For each
+              zonename on the command line, output an interval-format
+              description of the zone.  See "INTERVAL FORMAT" below.
+
+       -v     Output a verbose description of time intervals.  For each
+              zonename on the command line, print the time at the lowest
+              possible time value, the time one day after the lowest possible
+              time value, the times both one second before and exactly at each
+              detected time discontinuity, the time at one day less than the
+              highest possible time value, and the time at the highest
+              possible time value.  Each line is followed by isdst=D where D
+              is positive, zero, or negative depending on whether the given
+              time is daylight saving time, standard time, or an unknown time
+              type, respectively.  Each line is also followed by gmtoff=N if
+              the given local time is known to be N seconds east of Greenwich.
+
+       -V     Like -v, except omit the times relative to the extreme time
+              values.  This generates output that is easier to compare to that
+              of implementations with different time representations.
+
+       -c [loyear,]hiyear
+              Cut off interval output at the given year(s).  Cutoff times are
+              computed using the proleptic Gregorian calendar with year 0 and
+              with Universal Time (UT) ignoring leap seconds.  The lower bound
+              is exclusive and the upper is inclusive; for example, a loyear
+              of 1970 excludes a transition occurring at 1970-01-01 00:00:00
+              UTC but a hiyear of 1970 includes the transition.  The default
+              cutoff is -500,2500.
+
+       -t [lotime,]hitime
+              Cut off interval output at the given time(s), given in decimal
+              seconds since 1970-01-01 00:00:00 Coordinated Universal Time
+              (UTC).  The zonename determines whether the count includes leap
+              seconds.  As with -c, the cutoff's lower bound is exclusive and
+              its upper bound is inclusive.
+
+INTERVAL FORMAT
+       This format is experimental: it may change in future versions.
+
+       The interval format is a compact text representation that is intended
+       to be both human- and machine-readable.  It consists of an empty line,
+       then a line "TZ=string" where string is a double-quoted string giving
+       the zone name, a second line "- - interval" describing the time
+       interval before the first transition if any, and zero or more following
+       lines "date time interval", one line for each transition time and
+       following interval.  Fields are separated by single tabs.
+
+       Dates are in yyyy-mm-dd format and times are in 24-hour hh:mm:ss format
+       where hh<24.  Times are in local time immediately after the transition.
+       A time interval description consists of a UT offset in signed +-hhmmss
+       format, a time zone abbreviation, and an isdst flag.  An abbreviation
+       that equals the UT offset is omitted; other abbreviations are double-
+       quoted strings unless they consist of one or more alphabetic
+       characters.  An isdst flag is omitted for standard time, and otherwise
+       is a decimal integer that is unsigned and positive (typically 1) for
+       daylight saving time and negative for unknown.
+
+       In times and in UT offsets with absolute value less than 100 hours, the
+       seconds are omitted if they are zero, and the minutes are also omitted
+       if they are also zero.  Positive UT offsets are east of Greenwich.  The
+       UT offset -00 denotes a UT placeholder in areas where the actual offset
+       is unspecified; by convention, this occurs when the UT offset is zero
+       and the time zone abbreviation begins with "-" or is "zzz".
+
+       In double-quoted strings, escape sequences represent unusual
+       characters.  The escape sequences are \s for space, and \", \\, \f, \n,
+       \r, \t, and \v with their usual meaning in the C programming language.
+       E.g., the double-quoted string ""CET\s\"\\"" represents the character
+       sequence "CET "\".
+
+       Here is an example of the output, with the leading empty line omitted.
+       (This example is shown with tab stops set far enough apart so that the
+       tabbed columns line up.)
+
+         TZ="Pacific/Honolulu"
+         -          -          -10:31:26  LMT
+         1896-01-13 12:01:26   -10:30     HST
+         1933-04-30 03         -09:30     HDT        1
+         1933-05-21 11         -10:30     HST
+         1942-02-09 03         -09:30     HDT        1
+         1945-09-30 01         -10:30     HST
+         1947-06-08 02:30      -10        HST
+
+       Here, local time begins 10 hours, 31 minutes and 26 seconds west of UT,
+       and is a standard time abbreviated LMT.  Immediately after the first
+       transition, the date is 1896-01-13 and the time is 12:01:26, and the
+       following time interval is 10.5 hours west of UT, a standard time
+       abbreviated HST.  Immediately after the second transition, the date is
+       1933-04-30 and the time is 03:00:00 and the following time interval is
+       9.5 hours west of UT, is abbreviated HDT, and is daylight saving time.
+       Immediately after the last transition the date is 1947-06-08 and the
+       time is 02:30:00, and the following time interval is 10 hours west of
+       UT, a standard time abbreviated HST.
+
+       Here are excerpts from another example:
+
+         TZ="Europe/Astrakhan"
+         -          -          +03:12:12  LMT
+         1924-04-30 23:47:48   +03
+         1930-06-21 01         +04
+         1981-04-01 01         +05                   1
+         1981-09-30 23         +04
+         ...
+         2014-10-26 01         +03
+         2016-03-27 03         +04
+
+       This time zone is east of UT, so its UT offsets are positive.  Also,
+       many of its time zone abbreviations are omitted since they duplicate
+       the text of the UT offset.
+
+LIMITATIONS
+       Time discontinuities are found by sampling the results returned by
+       localtime at twelve-hour intervals.  This works in all real-world
+       cases; one can construct artificial time zones for which this fails.
+
+       In the -v and -V output, "UT" denotes the value returned by gmtime(3),
+       which uses UTC for modern time stamps and some other UT flavor for time
+       stamps that predate the introduction of UTC.  No attempt is currently
+       made to have the output use "UTC" for newer and "UT" for older time
+       stamps, partly because the exact date of the introduction of UTC is
+       problematic.
+
+SEE ALSO
+       newctime(3), tzfile(5), zic(8)
+
+                                                                      ZDUMP(8)
diff --git a/zdump.c b/zdump.c
new file mode 100644
index 000000000000..a4d91085348f
--- /dev/null
+++ b/zdump.c
@@ -0,0 +1,1116 @@
+/*
+** This file is in the public domain, so clarified as of
+** 2009-05-17 by Arthur David Olson.
+*/
+
+#include "version.h"
+
+#ifndef NETBSD_INSPIRED
+# define NETBSD_INSPIRED 1
+#endif
+
+#include "private.h"
+#include <stdio.h>
+
+#ifndef HAVE_SNPRINTF
+# define HAVE_SNPRINTF (199901 <= __STDC_VERSION__)
+#endif
+
+#ifndef HAVE_LOCALTIME_R
+# define HAVE_LOCALTIME_R 1
+#endif
+
+#ifndef HAVE_LOCALTIME_RZ
+# ifdef TM_ZONE
+#  define HAVE_LOCALTIME_RZ (NETBSD_INSPIRED && USE_LTZ)
+# else
+#  define HAVE_LOCALTIME_RZ 0
+# endif
+#endif
+
+#ifndef HAVE_TZSET
+# define HAVE_TZSET 1
+#endif
+
+#ifndef ZDUMP_LO_YEAR
+#define ZDUMP_LO_YEAR	(-500)
+#endif /* !defined ZDUMP_LO_YEAR */
+
+#ifndef ZDUMP_HI_YEAR
+#define ZDUMP_HI_YEAR	2500
+#endif /* !defined ZDUMP_HI_YEAR */
+
+#ifndef MAX_STRING_LENGTH
+#define MAX_STRING_LENGTH	1024
+#endif /* !defined MAX_STRING_LENGTH */
+
+#define SECSPERNYEAR	(SECSPERDAY * DAYSPERNYEAR)
+#define SECSPERLYEAR	(SECSPERNYEAR + SECSPERDAY)
+#define SECSPER400YEARS	(SECSPERNYEAR * (intmax_t) (300 + 3)	\
+			 + SECSPERLYEAR * (intmax_t) (100 - 3))
+
+/*
+** True if SECSPER400YEARS is known to be representable as an
+** intmax_t.  It's OK that SECSPER400YEARS_FITS can in theory be false
+** even if SECSPER400YEARS is representable, because when that happens
+** the code merely runs a bit more slowly, and this slowness doesn't
+** occur on any practical platform.
+*/
+enum { SECSPER400YEARS_FITS = SECSPERLYEAR <= INTMAX_MAX / 400 };
+
+#if HAVE_GETTEXT
+#include <locale.h>	/* for setlocale */
+#endif /* HAVE_GETTEXT */
+
+#if ! HAVE_LOCALTIME_RZ
+# undef  timezone_t
+# define timezone_t char **
+#endif
+
+#if !HAVE_POSIX_DECLS
+extern int	getopt(int argc, char * const argv[],
+			const char * options);
+extern char *	optarg;
+extern int	optind;
+#endif
+
+/* The minimum and maximum finite time values.  */
+enum { atime_shift = CHAR_BIT * sizeof (time_t) - 2 };
+static time_t const absolute_min_time =
+  ((time_t) -1 < 0
+   ? (- ((time_t) ~ (time_t) 0 < 0)
+      - (((time_t) 1 << atime_shift) - 1 + ((time_t) 1 << atime_shift)))
+   : 0);
+static time_t const absolute_max_time =
+  ((time_t) -1 < 0
+   ? (((time_t) 1 << atime_shift) - 1 + ((time_t) 1 << atime_shift))
+   : -1);
+static int	longest;
+static char *	progname;
+static bool	warned;
+static bool	errout;
+
+static char const *abbr(struct tm const *);
+static intmax_t	delta(struct tm *, struct tm *) ATTRIBUTE_PURE;
+static void dumptime(struct tm const *);
+static time_t hunt(timezone_t, char *, time_t, time_t);
+static void show(timezone_t, char *, time_t, bool);
+static void showtrans(char const *, struct tm const *, time_t, char const *,
+		      char const *);
+static const char *tformat(void);
+static time_t yeartot(intmax_t) ATTRIBUTE_PURE;
+
+/* Unlike <ctype.h>'s isdigit, this also works if c < 0 | c > UCHAR_MAX. */
+#define is_digit(c) ((unsigned)(c) - '0' <= 9)
+
+/* Is A an alphabetic character in the C locale?  */
+static bool
+is_alpha(char a)
+{
+	switch (a) {
+	  default:
+		return false;
+	  case 'A': case 'B': case 'C': case 'D': case 'E': case 'F': case 'G':
+	  case 'H': case 'I': case 'J': case 'K': case 'L': case 'M': case 'N':
+	  case 'O': case 'P': case 'Q': case 'R': case 'S': case 'T': case 'U':
+	  case 'V': case 'W': case 'X': case 'Y': case 'Z':
+	  case 'a': case 'b': case 'c': case 'd': case 'e': case 'f': case 'g':
+	  case 'h': case 'i': case 'j': case 'k': case 'l': case 'm': case 'n':
+	  case 'o': case 'p': case 'q': case 'r': case 's': case 't': case 'u':
+	  case 'v': case 'w': case 'x': case 'y': case 'z':
+		return true;
+	}
+}
+
+/* Return A + B, exiting if the result would overflow.  */
+static size_t
+sumsize(size_t a, size_t b)
+{
+  size_t sum = a + b;
+  if (sum < a) {
+    fprintf(stderr, "%s: size overflow\n", progname);
+    exit(EXIT_FAILURE);
+  }
+  return sum;
+}
+
+/* Return a pointer to a newly allocated buffer of size SIZE, exiting
+   on failure.  SIZE should be nonzero.  */
+static void * ATTRIBUTE_MALLOC
+xmalloc(size_t size)
+{
+  void *p = malloc(size);
+  if (!p) {
+    perror(progname);
+    exit(EXIT_FAILURE);
+  }
+  return p;
+}
+
+#if ! HAVE_TZSET
+# undef tzset
+# define tzset zdump_tzset
+static void tzset(void) { }
+#endif
+
+/* Assume gmtime_r works if localtime_r does.
+   A replacement localtime_r is defined below if needed.  */
+#if ! HAVE_LOCALTIME_R
+
+# undef gmtime_r
+# define gmtime_r zdump_gmtime_r
+
+static struct tm *
+gmtime_r(time_t *tp, struct tm *tmp)
+{
+  struct tm *r = gmtime(tp);
+  if (r) {
+    *tmp = *r;
+    r = tmp;
+  }
+  return r;
+}
+
+#endif
+
+/* Platforms with TM_ZONE don't need tzname, so they can use the
+   faster localtime_rz or localtime_r if available.  */
+
+#if defined TM_ZONE && HAVE_LOCALTIME_RZ
+# define USE_LOCALTIME_RZ true
+#else
+# define USE_LOCALTIME_RZ false
+#endif
+
+#if ! USE_LOCALTIME_RZ
+
+# if !defined TM_ZONE || ! HAVE_LOCALTIME_R || ! HAVE_TZSET
+#  undef localtime_r
+#  define localtime_r zdump_localtime_r
+static struct tm *
+localtime_r(time_t *tp, struct tm *tmp)
+{
+  struct tm *r = localtime(tp);
+  if (r) {
+    *tmp = *r;
+    r = tmp;
+  }
+  return r;
+}
+# endif
+
+# undef localtime_rz
+# define localtime_rz zdump_localtime_rz
+static struct tm *
+localtime_rz(timezone_t rz, time_t *tp, struct tm *tmp)
+{
+  return localtime_r(tp, tmp);
+}
+
+# ifdef TYPECHECK
+#  undef mktime_z
+#  define mktime_z zdump_mktime_z
+static time_t
+mktime_z(timezone_t tz, struct tm *tmp)
+{
+  return mktime(tmp);
+}
+# endif
+
+# undef tzalloc
+# undef tzfree
+# define tzalloc zdump_tzalloc
+# define tzfree zdump_tzfree
+
+static timezone_t
+tzalloc(char const *val)
+{
+  static char **fakeenv;
+  char **env = fakeenv;
+  char *env0;
+  if (! env) {
+    char **e = environ;
+    int to;
+
+    while (*e++)
+      continue;
+    env = xmalloc(sumsize(sizeof *environ,
+			  (e - environ) * sizeof *environ));
+    to = 1;
+    for (e = environ; (env[to] = *e); e++)
+      to += strncmp(*e, "TZ=", 3) != 0;
+  }
+  env0 = xmalloc(sumsize(sizeof "TZ=", strlen(val)));
+  env[0] = strcat(strcpy(env0, "TZ="), val);
+  environ = fakeenv = env;
+  tzset();
+  return env;
+}
+
+static void
+tzfree(timezone_t env)
+{
+  environ = env + 1;
+  free(env[0]);
+}
+#endif /* ! USE_LOCALTIME_RZ */
+
+/* A UT time zone, and its initializer.  */
+static timezone_t gmtz;
+static void
+gmtzinit(void)
+{
+  if (USE_LOCALTIME_RZ) {
+    static char const utc[] = "UTC0";
+    gmtz = tzalloc(utc);
+    if (!gmtz) {
+      perror(utc);
+      exit(EXIT_FAILURE);
+    }
+  }
+}
+
+/* Convert *TP to UT, storing the broken-down time into *TMP.
+   Return TMP if successful, NULL otherwise.  This is like gmtime_r(TP, TMP),
+   except typically faster if USE_LOCALTIME_RZ.  */
+static struct tm *
+my_gmtime_r(time_t *tp, struct tm *tmp)
+{
+  return USE_LOCALTIME_RZ ? localtime_rz(gmtz, tp, tmp) : gmtime_r(tp, tmp);
+}
+
+#ifndef TYPECHECK
+# define my_localtime_rz localtime_rz
+#else /* !defined TYPECHECK */
+
+static struct tm *
+my_localtime_rz(timezone_t tz, time_t *tp, struct tm *tmp)
+{
+	tmp = localtime_rz(tz, tp, tmp);
+	if (tmp) {
+		struct tm	tm;
+		register time_t	t;
+
+		tm = *tmp;
+		t = mktime_z(tz, &tm);
+		if (t != *tp) {
+			fflush(stdout);
+			fprintf(stderr, "\n%s: ", progname);
+			fprintf(stderr, tformat(), *tp);
+			fprintf(stderr, " ->");
+			fprintf(stderr, " year=%d", tmp->tm_year);
+			fprintf(stderr, " mon=%d", tmp->tm_mon);
+			fprintf(stderr, " mday=%d", tmp->tm_mday);
+			fprintf(stderr, " hour=%d", tmp->tm_hour);
+			fprintf(stderr, " min=%d", tmp->tm_min);
+			fprintf(stderr, " sec=%d", tmp->tm_sec);
+			fprintf(stderr, " isdst=%d", tmp->tm_isdst);
+			fprintf(stderr, " -> ");
+			fprintf(stderr, tformat(), t);
+			fprintf(stderr, "\n");
+			errout = true;
+		}
+	}
+	return tmp;
+}
+#endif /* !defined TYPECHECK */
+
+static void
+abbrok(const char *const abbrp, const char *const zone)
+{
+	register const char *	cp;
+	register const char *	wp;
+
+	if (warned)
+		return;
+	cp = abbrp;
+	while (is_alpha(*cp) || is_digit(*cp) || *cp == '-' || *cp == '+')
+		++cp;
+	if (cp - abbrp < 3)
+	  wp = _("has fewer than 3 characters");
+	else if (cp - abbrp > 6)
+	  wp = _("has more than 6 characters");
+	else if (*cp)
+	  wp = _("has characters other than ASCII alphanumerics, '-' or '+'");
+	else
+	  return;
+	fflush(stdout);
+	fprintf(stderr,
+		_("%s: warning: zone \"%s\" abbreviation \"%s\" %s\n"),
+		progname, zone, abbrp, wp);
+	warned = errout = true;
+}
+
+/* Return a time zone abbreviation.  If the abbreviation needs to be
+   saved, use *BUF (of size *BUFALLOC) to save it, and return the
+   abbreviation in the possibly-reallocated *BUF.  Otherwise, just
+   return the abbreviation.  Get the abbreviation from TMP.
+   Exit on memory allocation failure.  */
+static char const *
+saveabbr(char **buf, size_t *bufalloc, struct tm const *tmp)
+{
+  char const *ab = abbr(tmp);
+  if (HAVE_LOCALTIME_RZ)
+    return ab;
+  else {
+    size_t ablen = strlen(ab);
+    if (*bufalloc <= ablen) {
+      free(*buf);
+
+      /* Make the new buffer at least twice as long as the old,
+	 to avoid O(N**2) behavior on repeated calls.  */
+      *bufalloc = sumsize(*bufalloc, ablen + 1);
+
+      *buf = xmalloc(*bufalloc);
+    }
+    return strcpy(*buf, ab);
+  }
+}
+
+static void
+close_file(FILE *stream)
+{
+  char const *e = (ferror(stream) ? _("I/O error")
+		   : fclose(stream) != 0 ? strerror(errno) : NULL);
+  if (e) {
+    fprintf(stderr, "%s: %s\n", progname, e);
+    exit(EXIT_FAILURE);
+  }
+}
+
+static void
+usage(FILE * const stream, const int status)
+{
+	fprintf(stream,
+_("%s: usage: %s OPTIONS ZONENAME ...\n"
+  "Options include:\n"
+  "  -c [L,]U   Start at year L (default -500), end before year U (default 2500)\n"
+  "  -t [L,]U   Start at time L, end before time U (in seconds since 1970)\n"
+  "  -i         List transitions briefly (format is experimental)\n" \
+  "  -v         List transitions verbosely\n"
+  "  -V         List transitions a bit less verbosely\n"
+  "  --help     Output this help\n"
+  "  --version  Output version info\n"
+  "\n"
+  "Report bugs to %s.\n"),
+		progname, progname, REPORT_BUGS_TO);
+	if (status == EXIT_SUCCESS)
+	  close_file(stream);
+	exit(status);
+}
+
+int
+main(int argc, char *argv[])
+{
+	/* These are static so that they're initially zero.  */
+	static char *		abbrev;
+	static size_t		abbrevsize;
+
+	register int		i;
+	register bool		vflag;
+	register bool		Vflag;
+	register char *		cutarg;
+	register char *		cuttimes;
+	register time_t		cutlotime;
+	register time_t		cuthitime;
+	time_t			now;
+	bool iflag = false;
+
+	cutlotime = absolute_min_time;
+	cuthitime = absolute_max_time;
+#if HAVE_GETTEXT
+	setlocale(LC_ALL, "");
+#ifdef TZ_DOMAINDIR
+	bindtextdomain(TZ_DOMAIN, TZ_DOMAINDIR);
+#endif /* defined TEXTDOMAINDIR */
+	textdomain(TZ_DOMAIN);
+#endif /* HAVE_GETTEXT */
+	progname = argv[0];
+	for (i = 1; i < argc; ++i)
+		if (strcmp(argv[i], "--version") == 0) {
+			printf("zdump %s%s\n", PKGVERSION, TZVERSION);
+			return EXIT_SUCCESS;
+		} else if (strcmp(argv[i], "--help") == 0) {
+			usage(stdout, EXIT_SUCCESS);
+		}
+	vflag = Vflag = false;
+	cutarg = cuttimes = NULL;
+	for (;;)
+	  switch (getopt(argc, argv, "c:it:vV")) {
+	  case 'c': cutarg = optarg; break;
+	  case 't': cuttimes = optarg; break;
+	  case 'i': iflag = true; break;
+	  case 'v': vflag = true; break;
+	  case 'V': Vflag = true; break;
+	  case -1:
+	    if (! (optind == argc - 1 && strcmp(argv[optind], "=") == 0))
+	      goto arg_processing_done;
+	    /* Fall through.  */
+	  default:
+	    usage(stderr, EXIT_FAILURE);
+	  }
+ arg_processing_done:;
+
+	if (iflag | vflag | Vflag) {
+		intmax_t	lo;
+		intmax_t	hi;
+		char *loend, *hiend;
+		register intmax_t cutloyear = ZDUMP_LO_YEAR;
+		register intmax_t cuthiyear = ZDUMP_HI_YEAR;
+		if (cutarg != NULL) {
+			lo = strtoimax(cutarg, &loend, 10);
+			if (cutarg != loend && !*loend) {
+				hi = lo;
+				cuthiyear = hi;
+			} else if (cutarg != loend && *loend == ','
+				   && (hi = strtoimax(loend + 1, &hiend, 10),
+				       loend + 1 != hiend && !*hiend)) {
+				cutloyear = lo;
+				cuthiyear = hi;
+			} else {
+				fprintf(stderr, _("%s: wild -c argument %s\n"),
+					progname, cutarg);
+				return EXIT_FAILURE;
+			}
+		}
+		if (cutarg != NULL || cuttimes == NULL) {
+			cutlotime = yeartot(cutloyear);
+			cuthitime = yeartot(cuthiyear);
+		}
+		if (cuttimes != NULL) {
+			lo = strtoimax(cuttimes, &loend, 10);
+			if (cuttimes != loend && !*loend) {
+				hi = lo;
+				if (hi < cuthitime) {
+					if (hi < absolute_min_time)
+						hi = absolute_min_time;
+					cuthitime = hi;
+				}
+			} else if (cuttimes != loend && *loend == ','
+				   && (hi = strtoimax(loend + 1, &hiend, 10),
+				       loend + 1 != hiend && !*hiend)) {
+				if (cutlotime < lo) {
+					if (absolute_max_time < lo)
+						lo = absolute_max_time;
+					cutlotime = lo;
+				}
+				if (hi < cuthitime) {
+					if (hi < absolute_min_time)
+						hi = absolute_min_time;
+					cuthitime = hi;
+				}
+			} else {
+				fprintf(stderr,
+					_("%s: wild -t argument %s\n"),
+					progname, cuttimes);
+				return EXIT_FAILURE;
+			}
+		}
+	}
+	gmtzinit();
+	INITIALIZE (now);
+	if (! (iflag | vflag | Vflag))
+	  now = time(NULL);
+	longest = 0;
+	for (i = optind; i < argc; i++) {
+	  size_t arglen = strlen(argv[i]);
+	  if (longest < arglen)
+	    longest = arglen < INT_MAX ? arglen : INT_MAX;
+	}
+
+	for (i = optind; i < argc; ++i) {
+		timezone_t tz = tzalloc(argv[i]);
+		char const *ab;
+		time_t t;
+		struct tm tm, newtm;
+		bool tm_ok;
+		if (!tz) {
+		  perror(argv[i]);
+		  return EXIT_FAILURE;
+		}
+		if (! (iflag | vflag | Vflag)) {
+			show(tz, argv[i], now, false);
+			tzfree(tz);
+			continue;
+		}
+		warned = false;
+		t = absolute_min_time;
+		if (! (iflag | Vflag)) {
+			show(tz, argv[i], t, true);
+			t += SECSPERDAY;
+			show(tz, argv[i], t, true);
+		}
+		if (t < cutlotime)
+			t = cutlotime;
+		INITIALIZE (ab);
+		tm_ok = my_localtime_rz(tz, &t, &tm) != NULL;
+		if (tm_ok) {
+		  ab = saveabbr(&abbrev, &abbrevsize, &tm);
+		  if (iflag) {
+		    showtrans("\nTZ=%f", &tm, t, ab, argv[i]);
+		    showtrans("-\t-\t%Q", &tm, t, ab, argv[i]);
+		  }
+		}
+		while (t < cuthitime) {
+		  time_t newt = ((t < absolute_max_time - SECSPERDAY / 2
+				  && t + SECSPERDAY / 2 < cuthitime)
+				 ? t + SECSPERDAY / 2
+				 : cuthitime);
+		  struct tm *newtmp = localtime_rz(tz, &newt, &newtm);
+		  bool newtm_ok = newtmp != NULL;
+		  if (tm_ok != newtm_ok
+		      || (tm_ok && (delta(&newtm, &tm) != newt - t
+				    || newtm.tm_isdst != tm.tm_isdst
+				    || strcmp(abbr(&newtm), ab) != 0))) {
+		    newt = hunt(tz, argv[i], t, newt);
+		    newtmp = localtime_rz(tz, &newt, &newtm);
+		    newtm_ok = newtmp != NULL;
+		    if (iflag)
+		      showtrans("%Y-%m-%d\t%L\t%Q", newtmp, newt,
+				newtm_ok ? abbr(&newtm) : NULL, argv[i]);
+		    else {
+		      show(tz, argv[i], newt - 1, true);
+		      show(tz, argv[i], newt, true);
+		    }
+		  }
+		  t = newt;
+		  tm_ok = newtm_ok;
+		  if (newtm_ok) {
+		    ab = saveabbr(&abbrev, &abbrevsize, &newtm);
+		    tm = newtm;
+		  }
+		}
+		if (! (iflag | Vflag)) {
+			t = absolute_max_time;
+			t -= SECSPERDAY;
+			show(tz, argv[i], t, true);
+			t += SECSPERDAY;
+			show(tz, argv[i], t, true);
+		}
+		tzfree(tz);
+	}
+	close_file(stdout);
+	if (errout && (ferror(stderr) || fclose(stderr) != 0))
+	  return EXIT_FAILURE;
+	return EXIT_SUCCESS;
+}
+
+static time_t
+yeartot(intmax_t y)
+{
+	register intmax_t	myy, seconds, years;
+	register time_t		t;
+
+	myy = EPOCH_YEAR;
+	t = 0;
+	while (myy < y) {
+		if (SECSPER400YEARS_FITS && 400 <= y - myy) {
+			intmax_t diff400 = (y - myy) / 400;
+			if (INTMAX_MAX / SECSPER400YEARS < diff400)
+				return absolute_max_time;
+			seconds = diff400 * SECSPER400YEARS;
+			years = diff400 * 400;
+                } else {
+			seconds = isleap(myy) ? SECSPERLYEAR : SECSPERNYEAR;
+			years = 1;
+		}
+		myy += years;
+		if (t > absolute_max_time - seconds)
+			return absolute_max_time;
+		t += seconds;
+	}
+	while (y < myy) {
+		if (SECSPER400YEARS_FITS && y + 400 <= myy && myy < 0) {
+			intmax_t diff400 = (myy - y) / 400;
+			if (INTMAX_MAX / SECSPER400YEARS < diff400)
+				return absolute_min_time;
+			seconds = diff400 * SECSPER400YEARS;
+			years = diff400 * 400;
+		} else {
+			seconds = isleap(myy - 1) ? SECSPERLYEAR : SECSPERNYEAR;
+			years = 1;
+		}
+		myy -= years;
+		if (t < absolute_min_time + seconds)
+			return absolute_min_time;
+		t -= seconds;
+	}
+	return t;
+}
+
+static time_t
+hunt(timezone_t tz, char *name, time_t lot, time_t hit)
+{
+	static char *		loab;
+	static size_t		loabsize;
+	char const *		ab;
+	time_t			t;
+	struct tm		lotm;
+	struct tm		tm;
+	bool lotm_ok = my_localtime_rz(tz, &lot, &lotm) != NULL;
+	bool tm_ok;
+
+	if (lotm_ok)
+	  ab = saveabbr(&loab, &loabsize, &lotm);
+	for ( ; ; ) {
+		time_t diff = hit - lot;
+		if (diff < 2)
+			break;
+		t = lot;
+		t += diff / 2;
+		if (t <= lot)
+			++t;
+		else if (t >= hit)
+			--t;
+		tm_ok = my_localtime_rz(tz, &t, &tm) != NULL;
+		if (lotm_ok & tm_ok
+		    ? (delta(&tm, &lotm) == t - lot
+		       && tm.tm_isdst == lotm.tm_isdst
+		       && strcmp(abbr(&tm), ab) == 0)
+		    : lotm_ok == tm_ok) {
+		  lot = t;
+		  if (tm_ok)
+		    lotm = tm;
+		} else	hit = t;
+	}
+	return hit;
+}
+
+/*
+** Thanks to Paul Eggert for logic used in delta_nonneg.
+*/
+
+static intmax_t
+delta_nonneg(struct tm *newp, struct tm *oldp)
+{
+	register intmax_t	result;
+	register int		tmy;
+
+	result = 0;
+	for (tmy = oldp->tm_year; tmy < newp->tm_year; ++tmy)
+		result += DAYSPERNYEAR + isleap_sum(tmy, TM_YEAR_BASE);
+	result += newp->tm_yday - oldp->tm_yday;
+	result *= HOURSPERDAY;
+	result += newp->tm_hour - oldp->tm_hour;
+	result *= MINSPERHOUR;
+	result += newp->tm_min - oldp->tm_min;
+	result *= SECSPERMIN;
+	result += newp->tm_sec - oldp->tm_sec;
+	return result;
+}
+
+static intmax_t
+delta(struct tm *newp, struct tm *oldp)
+{
+  return (newp->tm_year < oldp->tm_year
+	  ? -delta_nonneg(oldp, newp)
+	  : delta_nonneg(newp, oldp));
+}
+
+#ifndef TM_GMTOFF
+/* Return A->tm_yday, adjusted to compare it fairly to B->tm_yday.
+   Assume A and B differ by at most one year.  */
+static int
+adjusted_yday(struct tm const *a, struct tm const *b)
+{
+  int yday = a->tm_yday;
+  if (b->tm_year < a->tm_year)
+    yday += 365 + isleap_sum(b->tm_year, TM_YEAR_BASE);
+  return yday;
+}
+#endif
+
+/* If A is the broken-down local time and B the broken-down UT for
+   the same instant, return A's UT offset in seconds, where positive
+   offsets are east of Greenwich.  On failure, return LONG_MIN.
+
+   If T is nonnull, *T is the timestamp that corresponds to A; call
+   my_gmtime_r and use its result instead of B.  Otherwise, B is the
+   possibly nonnull result of an earlier call to my_gmtime_r.  */
+static long
+gmtoff(struct tm const *a, time_t *t, struct tm const *b)
+{
+#ifdef TM_GMTOFF
+  return a->TM_GMTOFF;
+#else
+  struct tm tm;
+  if (t)
+    b = my_gmtime_r(t, &tm);
+  if (! b)
+    return LONG_MIN;
+  else {
+    int ayday = adjusted_yday(a, b);
+    int byday = adjusted_yday(b, a);
+    int days = ayday - byday;
+    long hours = a->tm_hour - b->tm_hour + 24 * days;
+    long minutes = a->tm_min - b->tm_min + 60 * hours;
+    long seconds = a->tm_sec - b->tm_sec + 60 * minutes;
+    return seconds;
+  }
+#endif
+}
+
+static void
+show(timezone_t tz, char *zone, time_t t, bool v)
+{
+	register struct tm *	tmp;
+	register struct tm *	gmtmp;
+	struct tm tm, gmtm;
+
+	printf("%-*s  ", longest, zone);
+	if (v) {
+		gmtmp = my_gmtime_r(&t, &gmtm);
+		if (gmtmp == NULL) {
+			printf(tformat(), t);
+		} else {
+			dumptime(gmtmp);
+			printf(" UT");
+		}
+		printf(" = ");
+	}
+	tmp = my_localtime_rz(tz, &t, &tm);
+	dumptime(tmp);
+	if (tmp != NULL) {
+		if (*abbr(tmp) != '\0')
+			printf(" %s", abbr(tmp));
+		if (v) {
+			long off = gmtoff(tmp, NULL, gmtmp);
+			printf(" isdst=%d", tmp->tm_isdst);
+			if (off != LONG_MIN)
+			  printf(" gmtoff=%ld", off);
+		}
+	}
+	printf("\n");
+	if (tmp != NULL && *abbr(tmp) != '\0')
+		abbrok(abbr(tmp), zone);
+}
+
+#if HAVE_SNPRINTF
+# define my_snprintf snprintf
+#else
+# include <stdarg.h>
+
+/* A substitute for snprintf that is good enough for zdump.  */
+static int ATTRIBUTE_FORMAT((printf, 3, 4))
+my_snprintf(char *s, size_t size, char const *format, ...)
+{
+  int n;
+  va_list args;
+  char const *arg;
+  size_t arglen, slen;
+  char buf[1024];
+  va_start(args, format);
+  if (strcmp(format, "%s") == 0) {
+    arg = va_arg(args, char const *);
+    arglen = strlen(arg);
+  } else {
+    n = vsprintf(buf, format, args);
+    if (n < 0)
+      return n;
+    arg = buf;
+    arglen = n;
+  }
+  slen = arglen < size ? arglen : size - 1;
+  memcpy(s, arg, slen);
+  s[slen] = '\0';
+  n = arglen <= INT_MAX ? arglen : -1;
+  va_end(args);
+  return n;
+}
+#endif
+
+/* Store into BUF, of size SIZE, a formatted local time taken from *TM.
+   Use ISO 8601 format +HH:MM:SS.  Omit :SS if SS is zero, and omit
+   :MM too if MM is also zero.
+
+   Return the length of the resulting string.  If the string does not
+   fit, return the length that the string would have been if it had
+   fit; do not overrun the output buffer.  */
+static int
+format_local_time(char *buf, size_t size, struct tm const *tm)
+{
+  int ss = tm->tm_sec, mm = tm->tm_min, hh = tm->tm_hour;
+  return (ss
+	  ? my_snprintf(buf, size, "%02d:%02d:%02d", hh, mm, ss)
+	  : mm
+	  ? my_snprintf(buf, size, "%02d:%02d", hh, mm)
+	  : my_snprintf(buf, size, "%02d", hh));
+}
+
+/* Store into BUF, of size SIZE, a formatted UT offset for the
+   localtime *TM corresponding to time T.  Use ISO 8601 format
+   +HHMMSS, or -HHMMSS for timestamps west of Greenwich; use the
+   format -00 for unknown UT offsets.  If the hour needs more than
+   two digits to represent, extend the length of HH as needed.
+   Otherwise, omit SS if SS is zero, and omit MM too if MM is also
+   zero.
+
+   Return the length of the resulting string, or -1 if the result is
+   not representable as a string.  If the string does not fit, return
+   the length that the string would have been if it had fit; do not
+   overrun the output buffer.  */
+static int
+format_utc_offset(char *buf, size_t size, struct tm const *tm, time_t t)
+{
+  long off = gmtoff(tm, &t, NULL);
+  char sign = ((off < 0
+		|| (off == 0
+		    && (*abbr(tm) == '-' || strcmp(abbr(tm), "zzz") == 0)))
+	       ? '-' : '+');
+  long hh;
+  int mm, ss;
+  if (off < 0)
+    {
+      if (off == LONG_MIN)
+	return -1;
+      off = -off;
+    }
+  ss = off % 60;
+  mm = off / 60 % 60;
+  hh = off / 60 / 60;
+  return (ss || 100 <= hh
+	  ? my_snprintf(buf, size, "%c%02ld%02d%02d", sign, hh, mm, ss)
+	  : mm
+	  ? my_snprintf(buf, size, "%c%02ld%02d", sign, hh, mm)
+	  : my_snprintf(buf, size, "%c%02ld", sign, hh));
+}
+
+/* Store into BUF (of size SIZE) a quoted string representation of P.
+   If the representation's length is less than SIZE, return the
+   length; the representation is not null terminated.  Otherwise
+   return SIZE, to indicate that BUF is too small.  */
+static size_t
+format_quoted_string(char *buf, size_t size, char const *p)
+{
+  char *b = buf;
+  size_t s = size;
+  if (!s)
+    return size;
+  *b++ = '"', s--;
+  for (;;) {
+    char c = *p++;
+    if (s <= 1)
+      return size;
+    switch (c) {
+    default: *b++ = c, s--; continue;
+    case '\0': *b++ = '"', s--; return size - s;
+    case '"': case '\\': break;
+    case ' ': c = 's'; break;
+    case '\f': c = 'f'; break;
+    case '\n': c = 'n'; break;
+    case '\r': c = 'r'; break;
+    case '\t': c = 't'; break;
+    case '\v': c = 'v'; break;
+    }
+    *b++ = '\\', *b++ = c, s -= 2;
+  }
+}
+
+/* Store into BUF (of size SIZE) a timestamp formatted by TIME_FMT.
+   TM is the broken-down time, T the seconds count, AB the time zone
+   abbreviation, and ZONE_NAME the zone name.  Return true if
+   successful, false if the output would require more than SIZE bytes.
+   TIME_FMT uses the same format that strftime uses, with these
+   additions:
+
+   %f zone name
+   %L local time as per format_local_time
+   %Q like "U\t%Z\tD" where U is the UT offset as for format_utc_offset
+      and D is the isdst flag; except omit D if it is zero, omit %Z if
+      it equals U, quote and escape %Z if it contains nonalphabetics,
+      and omit any trailing tabs.  */
+
+static bool
+istrftime(char *buf, size_t size, char const *time_fmt,
+	  struct tm const *tm, time_t t, char const *ab, char const *zone_name)
+{
+  char *b = buf;
+  size_t s = size;
+  char const *f = time_fmt, *p;
+
+  for (p = f; ; p++)
+    if (*p == '%' && p[1] == '%')
+      p++;
+    else if (!*p
+	     || (*p == '%'
+		 && (p[1] == 'f' || p[1] == 'L' || p[1] == 'Q'))) {
+      size_t formatted_len;
+      size_t f_prefix_len = p - f;
+      size_t f_prefix_copy_size = p - f + 2;
+      char fbuf[100];
+      bool oversized = sizeof fbuf <= f_prefix_copy_size;
+      char *f_prefix_copy = oversized ? xmalloc(f_prefix_copy_size) : fbuf;
+      memcpy(f_prefix_copy, f, f_prefix_len);
+      strcpy(f_prefix_copy + f_prefix_len, "X");
+      formatted_len = strftime(b, s, f_prefix_copy, tm);
+      if (oversized)
+	free(f_prefix_copy);
+      if (formatted_len == 0)
+	return false;
+      formatted_len--;
+      b += formatted_len, s -= formatted_len;
+      if (!*p++)
+	break;
+      switch (*p) {
+      case 'f':
+	formatted_len = format_quoted_string(b, s, zone_name);
+	break;
+      case 'L':
+	formatted_len = format_local_time(b, s, tm);
+	break;
+      case 'Q':
+	{
+	  bool show_abbr;
+	  int offlen = format_utc_offset(b, s, tm, t);
+	  if (! (0 <= offlen && offlen < s))
+	    return false;
+	  show_abbr = strcmp(b, ab) != 0;
+	  b += offlen, s -= offlen;
+	  if (show_abbr) {
+	    char const *abp;
+	    size_t len;
+	    if (s <= 1)
+	      return false;
+	    *b++ = '\t', s--;
+	    for (abp = ab; is_alpha(*abp); abp++)
+	      continue;
+	    len = (!*abp && *ab
+		   ? my_snprintf(b, s, "%s", ab)
+		   : format_quoted_string(b, s, ab));
+	    if (s <= len)
+	      return false;
+	    b += len, s -= len;
+	  }
+	  formatted_len
+	    = (tm->tm_isdst
+	       ? my_snprintf(b, s, &"\t\t%d"[show_abbr], tm->tm_isdst)
+	       : 0);
+	}
+	break;
+      }
+      if (s <= formatted_len)
+	return false;
+      b += formatted_len, s -= formatted_len;
+      f = p + 1;
+    }
+  *b = '\0';
+  return true;
+}
+
+/* Show a time transition.  */
+static void
+showtrans(char const *time_fmt, struct tm const *tm, time_t t, char const *ab,
+	  char const *zone_name)
+{
+  if (!tm) {
+    printf(tformat(), t);
+    putchar('\n');
+  } else {
+    char stackbuf[1000];
+    size_t size = sizeof stackbuf;
+    char *buf = stackbuf;
+    char *bufalloc = NULL;
+    while (! istrftime(buf, size, time_fmt, tm, t, ab, zone_name)) {
+      size = sumsize(size, size);
+      free(bufalloc);
+      buf = bufalloc = xmalloc(size);
+    }
+    puts(buf);
+    free(bufalloc);
+  }
+}
+
+static char const *
+abbr(struct tm const *tmp)
+{
+#ifdef TM_ZONE
+	return tmp->TM_ZONE;
+#else
+# if HAVE_TZNAME
+	if (0 <= tmp->tm_isdst && tzname[0 < tmp->tm_isdst])
+	  return tzname[0 < tmp->tm_isdst];
+# endif
+	return "";
+#endif
+}
+
+/*
+** The code below can fail on certain theoretical systems;
+** it works on all known real-world systems as of 2004-12-30.
+*/
+
+static const char *
+tformat(void)
+{
+	if (0 > (time_t) -1) {		/* signed */
+		if (sizeof (time_t) == sizeof (intmax_t))
+			return "%"PRIdMAX;
+		if (sizeof (time_t) > sizeof (long))
+			return "%lld";
+		if (sizeof (time_t) > sizeof (int))
+			return "%ld";
+		return "%d";
+	}
+#ifdef PRIuMAX
+	if (sizeof (time_t) == sizeof (uintmax_t))
+		return "%"PRIuMAX;
+#endif
+	if (sizeof (time_t) > sizeof (unsigned long))
+		return "%llu";
+	if (sizeof (time_t) > sizeof (unsigned int))
+		return "%lu";
+	return "%u";
+}
+
+static void
+dumptime(register const struct tm *timeptr)
+{
+	static const char	wday_name[][4] = {
+		"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
+	};
+	static const char	mon_name[][4] = {
+		"Jan", "Feb", "Mar", "Apr", "May", "Jun",
+		"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
+	};
+	register const char *	wn;
+	register const char *	mn;
+	register int		lead;
+	register int		trail;
+
+	if (timeptr == NULL) {
+		printf("NULL");
+		return;
+	}
+	/*
+	** The packaged localtime_rz and gmtime_r never put out-of-range
+	** values in tm_wday or tm_mon, but since this code might be compiled
+	** with other (perhaps experimental) versions, paranoia is in order.
+	*/
+	if (timeptr->tm_wday < 0 || timeptr->tm_wday >=
+		(int) (sizeof wday_name / sizeof wday_name[0]))
+			wn = "???";
+	else		wn = wday_name[timeptr->tm_wday];
+	if (timeptr->tm_mon < 0 || timeptr->tm_mon >=
+		(int) (sizeof mon_name / sizeof mon_name[0]))
+			mn = "???";
+	else		mn = mon_name[timeptr->tm_mon];
+	printf("%s %s%3d %.2d:%.2d:%.2d ",
+		wn, mn,
+		timeptr->tm_mday, timeptr->tm_hour,
+		timeptr->tm_min, timeptr->tm_sec);
+#define DIVISOR	10
+	trail = timeptr->tm_year % DIVISOR + TM_YEAR_BASE % DIVISOR;
+	lead = timeptr->tm_year / DIVISOR + TM_YEAR_BASE / DIVISOR +
+		trail / DIVISOR;
+	trail %= DIVISOR;
+	if (trail < 0 && lead > 0) {
+		trail += DIVISOR;
+		--lead;
+	} else if (lead < 0 && trail > 0) {
+		trail -= DIVISOR;
+		++lead;
+	}
+	if (lead == 0)
+		printf("%d", trail);
+	else	printf("%d%d", lead, ((trail < 0) ? -trail : trail));
+}
diff --git a/zic.8 b/zic.8
new file mode 100644
index 000000000000..d105b24002cc
--- /dev/null
+++ b/zic.8
@@ -0,0 +1,599 @@
+.TH ZIC 8
+.SH NAME
+zic \- time zone compiler
+.SH SYNOPSIS
+.B zic
+[
+.I option
+\&... ] [
+.I filename
+\&... ]
+.SH DESCRIPTION
+.ie '\(lq'' .ds lq \&"\"
+.el .ds lq \(lq\"
+.ie '\(rq'' .ds rq \&"\"
+.el .ds rq \(rq\"
+.de q
+\\$3\*(lq\\$1\*(rq\\$2
+..
+.ie '\(la'' .ds < <
+.el .ds < \(la
+.ie '\(ra'' .ds > >
+.el .ds > \(ra
+.ie \n(.g \{\
+.  ds : \:
+.  ds - \f(CW-\fP
+.\}
+.el \{\
+.  ds :
+.  ds - \-
+.\}
+.I Zic
+reads text from the file(s) named on the command line
+and creates the time conversion information files specified in this input.
+If a
+.I filename
+is
+.q "\*-" ,
+the standard input is read.
+.PP
+These options are available:
+.TP
+.BI "\*-\*-version"
+Output version information and exit.
+.TP
+.BI "\*-d " directory
+Create time conversion information files in the named directory rather than
+in the standard directory named below.
+.TP
+.BI "\*-l " timezone
+Use the given time zone as local time.
+.I Zic
+will act as if the input contained a link line of the form
+.sp
+.ti +.5i
+Link	\fItimezone\fP		localtime
+.TP
+.BI "\*-p " timezone
+Use the given time zone's rules when handling POSIX-format
+time zone environment variables.
+.I Zic
+will act as if the input contained a link line of the form
+.sp
+.ti +.5i
+Link	\fItimezone\fP		posixrules
+.TP
+.BI "\*-t " file
+When creating local time information, put the configuration link in
+the named file rather than in the standard location.
+.TP
+.BI "\*-L " leapsecondfilename
+Read leap second information from the file with the given name.
+If this option is not used,
+no leap second information appears in output files.
+.TP
+.B \*-v
+Be more verbose, and complain about the following situations:
+.RS
+.PP
+The input specifies a link to a link.
+.PP
+A year that appears in a data file is outside the range
+of years representable by
+.IR time (2)
+values.
+.PP
+A time of 24:00 or more appears in the input.
+Pre-1998 versions of
+.I zic
+prohibit 24:00, and pre-2007 versions prohibit times greater than 24:00.
+.PP
+A rule goes past the start or end of the month.
+Pre-2004 versions of
+.I zic
+prohibit this.
+.PP
+The output file does not contain all the information about the
+long-term future of a zone, because the future cannot be summarized as
+an extended POSIX TZ string.  For example, as of 2013 this problem
+occurs for Iran's daylight-saving rules for the predicted future, as
+these rules are based on the Iranian calendar, which cannot be
+represented.
+.PP
+The output contains data that may not be handled properly by client
+code designed for older
+.I zic
+output formats.  These compatibility issues affect only time stamps
+before 1970 or after the start of 2038.
+.PP
+A time zone abbreviation has fewer than 3 characters.
+POSIX requires at least 3.
+.PP
+An output file name contains a byte that is not an ASCII letter,
+.q "\*-" ,
+.q "/" ,
+or
+.q "_" ;
+or it contains a file name component that contains more than 14 bytes
+or that starts with
+.q "\*-" .
+.RE
+.TP
+.B \*-s
+Limit time values stored in output files to values that are the same
+whether they're taken to be signed or unsigned.
+You can use this option to generate SVVS-compatible files.
+.PP
+Input files should be text files, that is, they should be a series of
+zero or more lines, each ending in a newline byte and containing at
+most 511 bytes, and without any NUL bytes.  The input text's encoding
+is typically UTF-8 or ASCII; it should have a unibyte representation
+for the POSIX Portable Character Set (PPCS)
+\*<http://pubs\*:.opengroup\*:.org/\*:onlinepubs/\*:9699919799/\*:basedefs/\*:V1_chap06\*:.html\*>
+and the encoding's non-unibyte characters should consist entirely of
+non-PPCS bytes.  Non-PPCS characters typically occur only in comments:
+although output file names and time zone abbreviations can contain
+nearly any character, other software will work better if these are
+limited to the restricted syntax described under the
+.B \*-v
+option.
+.PP
+Input lines are made up of fields.
+Fields are separated from one another by one or more white space characters.
+The white space characters are space, form feed, carriage return, newline,
+tab, and vertical tab.
+Leading and trailing white space on input lines is ignored.
+An unquoted sharp character (#) in the input introduces a comment which extends
+to the end of the line the sharp character appears on.
+White space characters and sharp characters may be enclosed in double quotes
+(") if they're to be used as part of a field.
+Any line that is blank (after comment stripping) is ignored.
+Non-blank lines are expected to be of one of three types:
+rule lines, zone lines, and link lines.
+.PP
+Names must be in English and are case insensitive.
+They appear in several contexts, and include month and weekday names
+and keywords such as
+.BR "maximum" ,
+.BR "only" ,
+.BR "Rolling" ,
+and
+.BR "Zone" .
+A name can be abbreviated by omitting all but an initial prefix; any
+abbreviation must be unambiguous in context.
+.PP
+A rule line has the form
+.nf
+.ti +.5i
+.ta \w'Rule\0\0'u +\w'NAME\0\0'u +\w'FROM\0\0'u +\w'1973\0\0'u +\w'TYPE\0\0'u +\w'Apr\0\0'u +\w'lastSun\0\0'u +\w'2:00s\0\0'u +\w'1:00d\0\0'u
+.sp
+Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+.sp
+For example:
+.ti +.5i
+.sp
+Rule	US	1967	1973	\*-	Apr	lastSun	2:00s	1:00d	D
+.sp
+.fi
+The fields that make up a rule line are:
+.TP "\w'LETTER/S'u"
+.B NAME
+Gives the (arbitrary) name of the set of rules this rule is part of.
+.TP
+.B FROM
+Gives the first year in which the rule applies.
+Any signed integer year can be supplied; the proleptic Gregorian calendar
+is assumed, with year 0 preceding year 1.
+The word
+.B minimum
+(or an abbreviation) means the indefinite past.
+The word
+.B maximum
+(or an abbreviation) means the indefinite future.
+Rules can describe times that are not representable as time values,
+with the unrepresentable times ignored; this allows rules to be portable
+among hosts with differing time value types.
+.TP
+.B TO
+Gives the final year in which the rule applies.
+In addition to
+.B minimum
+and
+.B maximum
+(as above),
+the word
+.B only
+(or an abbreviation)
+may be used to repeat the value of the
+.B FROM
+field.
+.TP
+.B TYPE
+should be
+.q \*-
+and is present for compatibility with older versions of
+.I zic
+in which it could contain year types.
+.TP
+.B IN
+Names the month in which the rule takes effect.
+Month names may be abbreviated.
+.TP
+.B ON
+Gives the day on which the rule takes effect.
+Recognized forms include:
+.nf
+.in +.5i
+.sp
+.ta \w'Sun<=25\0\0'u
+5	the fifth of the month
+lastSun	the last Sunday in the month
+lastMon	the last Monday in the month
+Sun>=8	first Sunday on or after the eighth
+Sun<=25	last Sunday on or before the 25th
+.fi
+.in -.5i
+.sp
+A weekday name (e.g.,
+.BR "Sunday" )
+or a weekday name preceded by
+.q "last"
+(e.g.,
+.BR "lastSunday" )
+may be abbreviated or spelled out in full.
+Note that there must be no spaces within the
+.B ON
+field.
+.TP
+.B AT
+Gives the time of day at which the rule takes effect.
+Recognized forms include:
+.nf
+.in +.5i
+.sp
+.ta \w'00:19:32.13\0\0'u
+2	time in hours
+2:00	time in hours and minutes
+01:28:14	time in hours, minutes, and seconds
+00:19:32.13	time with fractional seconds
+15:00	24-hour format time (for times after noon)
+260:00	260 hours after 00:00
+\*-2:30	2.5 hours before 00:00
+\*-	equivalent to 0
+.fi
+.in -.5i
+.sp
+where hour 0 is midnight at the start of the day,
+and hour 24 is midnight at the end of the day.
+Although
+.I zic
+rounds times to the nearest integer second
+(breaking ties to the even integer), the fractions may be useful
+to other applications requiring greater precision.
+The source format does not specify any maximum precision.
+Any of these forms may be followed by the letter
+.B w
+if the given time is local
+.q "wall clock"
+time,
+.B s
+if the given time is local
+.q "standard"
+time, or
+.B u
+(or
+.B g
+or
+.BR z )
+if the given time is universal time;
+in the absence of an indicator,
+wall clock time is assumed.
+The intent is that a rule line describes the instants when a
+clock/calendar set to the type of time specified in the
+.B AT
+field would show the specified date and time of day.
+.TP
+.B SAVE
+Gives the amount of time to be added to local standard time when the rule is in
+effect, and whether the resulting time is standard or daylight saving.
+This field has the same format as the
+.B AT
+field
+except with a different set of suffix letters:
+.B s
+for standard time and
+.B d
+for daylight saving time.
+The suffix letter is typically omitted, and defaults to
+.B s
+if the offset is zero and to
+.B d
+otherwise.
+Negative offsets are allowed; in Ireland, for example, daylight saving
+time is observed in winter and has a negative offset relative to
+Irish Standard Time.
+The offset is merely added to standard time; for example,
+.I zic
+does not distinguish a 10:30 standard time plus an 0:30
+.B SAVE
+from a 10:00 standard time plus a 1:00
+.BR SAVE .
+.TP
+.B LETTER/S
+Gives the
+.q "variable part"
+(for example, the
+.q "S"
+or
+.q "D"
+in
+.q "EST"
+or
+.q "EDT" )
+of time zone abbreviations to be used when this rule is in effect.
+If this field is
+.q \*- ,
+the variable part is null.
+.PP
+A zone line has the form
+.sp
+.nf
+.ti +.5i
+.ta \w'Zone\0\0'u +\w'Asia/Amman\0\0'u +\w'GMTOFF\0\0'u +\w'Jordan\0\0'u +\w'FORMAT\0\0'u
+Zone	NAME	GMTOFF	RULES	FORMAT	[UNTIL]
+.sp
+For example:
+.sp
+.ti +.5i
+Zone	Asia/Amman	2:00	Jordan	EE%sT	2017 Oct 27 01:00
+.sp
+.fi
+The fields that make up a zone line are:
+.TP "\w'GMTOFF'u"
+.B NAME
+The name of the time zone.
+This is the name used in creating the time conversion information file for the
+zone.
+It should not contain a file name component
+.q ".\&"
+or
+.q ".." ;
+a file name component is a maximal substring that does not contain
+.q "/" .
+.TP
+.B GMTOFF
+The amount of time to add to UT to get standard time in this zone.
+This field has the same format as the
+.B AT
+and
+.B SAVE
+fields of rule lines;
+begin the field with a minus sign if time must be subtracted from UT.
+.TP
+.B RULES
+The name of the rules that apply in the time zone or,
+alternatively, a field in the same format as a rule-line SAVE column,
+giving of the amount of time to be added to local standard time
+effect, and whether the resulting time is standard or daylight saving.
+If this field is
+.B \*-
+then standard time always applies in the time zone.
+When an amount of time is given, only the sum of standard time and
+this amount matters.
+.TP
+.B FORMAT
+The format for time zone abbreviations in this time zone.
+The pair of characters
+.B %s
+is used to show where the
+.q "variable part"
+of the time zone abbreviation goes.
+Alternatively, a format can use the pair of characters
+.B %z
+to stand for the UT offset in the form
+.RI \(+- hh ,
+.RI \(+- hhmm ,
+or
+.RI \(+- hhmmss ,
+using the shortest form that does not lose information, where
+.IR hh ,
+.IR mm ,
+and
+.I ss
+are the hours, minutes, and seconds east (+) or west (\(mi) of UT.
+Alternatively,
+a slash (/)
+separates standard and daylight abbreviations.
+To conform to POSIX, a time zone abbreviation should contain only
+alphanumeric ASCII characters, "+" and "\*-".
+.TP
+.B UNTIL
+The time at which the UT offset or the rule(s) change for a location.
+It takes the form of YEAR [MONTH [DAY [TIME]]].
+If this is specified,
+the time zone information is generated from the given UT offset
+and rule change until the time specified, which is interpreted using
+the rules in effect just before the transition.
+The month, day, and time of day have the same format as the IN, ON, and AT
+fields of a rule; trailing fields can be omitted, and default to the
+earliest possible value for the missing fields.
+.IP
+The next line must be a
+.q "continuation"
+line; this has the same form as a zone line except that the
+string
+.q "Zone"
+and the name are omitted, as the continuation line will
+place information starting at the time specified as the
+.q "until"
+information in the previous line in the file used by the previous line.
+Continuation lines may contain
+.q "until"
+information, just as zone lines do, indicating that the next line is a further
+continuation.
+.PP
+If a zone changes at the same instant that a rule would otherwise take
+effect in the earlier zone or continuation line, the rule is ignored.
+In a single zone it is an error if two rules take effect at the same
+instant, or if two zone changes take effect at the same instant.
+.PP
+A link line has the form
+.sp
+.nf
+.ti +.5i
+.ta \w'Link\0\0'u +\w'Europe/Istanbul\0\0'u
+Link	TARGET	LINK-NAME
+.sp
+For example:
+.sp
+.ti +.5i
+Link	Europe/Istanbul	Asia/Istanbul
+.sp
+.fi
+The
+.B TARGET
+field should appear as the
+.B NAME
+field in some zone line.
+The
+.B LINK-NAME
+field is used as an alternative name for that zone;
+it has the same syntax as a zone line's
+.B NAME
+field.
+.PP
+Except for continuation lines,
+lines may appear in any order in the input.
+However, the behavior is unspecified if multiple zone or link lines
+define the same name, or if the source of one link line is the target
+of another.
+.PP
+Lines in the file that describes leap seconds have the following form:
+.nf
+.ti +.5i
+.ta \w'Leap\0\0'u +\w'YEAR\0\0'u +\w'MONTH\0\0'u +\w'DAY\0\0'u +\w'HH:MM:SS\0\0'u +\w'CORR\0\0'u
+.sp
+Leap	YEAR	MONTH	DAY	HH:MM:SS	CORR	R/S
+.sp
+For example:
+.ti +.5i
+.sp
+Leap	2016	Dec	31	23:59:60	+	S
+.sp
+.fi
+The
+.BR YEAR ,
+.BR MONTH ,
+.BR DAY ,
+and
+.B HH:MM:SS
+fields tell when the leap second happened.
+The
+.B CORR
+field
+should be
+.q "+"
+if a second was added
+or
+.q "\*-"
+if a second was skipped.
+The
+.B R/S
+field
+should be (an abbreviation of)
+.q "Stationary"
+if the leap second time given by the other fields should be interpreted as UTC
+or
+(an abbreviation of)
+.q "Rolling"
+if the leap second time given by the other fields should be interpreted as
+local wall clock time.
+.SH "EXTENDED EXAMPLE"
+Here is an extended example of
+.I zic
+input, intended to illustrate many of its features.
+In this example, the EU rules are for the European Union
+and for its predecessor organization, the European Communities.
+.br
+.ne 22
+.nf
+.in +2m
+.ta \w'# Rule\0\0'u +\w'NAME\0\0'u +\w'FROM\0\0'u +\w'1973\0\0'u +\w'TYPE\0\0'u +\w'Apr\0\0'u +\w'lastSun\0\0'u +\w'2:00\0\0'u +\w'SAVE\0\0'u
+.sp
+# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+Rule	Swiss	1941	1942	\*-	May	Mon>=1	1:00	1:00	S
+Rule	Swiss	1941	1942	\*-	Oct	Mon>=1	2:00	0	\*-
+.sp .5
+Rule	EU	1977	1980	\*-	Apr	Sun>=1	1:00u	1:00	S
+Rule	EU	1977	only	\*-	Sep	lastSun	1:00u	0	\*-
+Rule	EU	1978	only	\*-	Oct	 1	1:00u	0	\*-
+Rule	EU	1979	1995	\*-	Sep	lastSun	1:00u	0	\*-
+Rule	EU	1981	max	\*-	Mar	lastSun	1:00u	1:00	S
+Rule	EU	1996	max	\*-	Oct	lastSun	1:00u	0	\*-
+.sp
+.ta \w'# Zone\0\0'u +\w'Europe/Zurich\0\0'u +\w'GMTOFF\0\0'u +\w'0:34:08\0\0'u +\w'FORMAT\0\0'u
+# Zone	NAME	GMTOFF	RULES	FORMAT	[UNTIL]
+Zone	Europe/Zurich	0:34:08	\*-	LMT	1853 Jul 16
+		0:29:46	\*-	BMT	1894 Jun
+		1:00	Swiss	CE%sT	1981
+		1:00	EU	CE%sT
+.sp
+Link	Europe/Zurich	Europe/Vaduz
+.sp
+.in
+.fi
+In this example, the zone is named Europe/Zurich but it has an alias
+as Europe/Vaduz.  This example says that Zurich was 34 minutes and 8
+seconds east of UT until 1853-07-16 at 00:00, when the legal offset
+was changed to 7\(de\|26\(fm\|22.50\(sd; although this works out to
+0:29:45.50, the input format cannot represent fractional seconds so it
+is rounded here.  After 1894-06-01 at 00:00 the UT offset became one hour
+and Swiss daylight saving rules (defined with lines beginning with "Rule
+Swiss") apply.  From 1981 to the present, EU daylight saving rules have
+applied, and the UTC offset has remained at one hour.
+.PP
+In 1941 and 1942, daylight saving time applied from the first Monday
+in May at 01:00 to the first Monday in October at 02:00.
+The pre-1981 EU daylight-saving rules have no effect
+here, but are included for completeness.  Since 1981, daylight
+saving has begun on the last Sunday in March at 01:00 UTC.
+Until 1995 it ended the last Sunday in September at 01:00 UTC,
+but this changed to the last Sunday in October starting in 1996.
+.PP
+For purposes of
+display, "LMT" and "BMT" were initially used, respectively.  Since
+Swiss rules and later EU rules were applied, the display name for the
+time zone has been CET for standard time and CEST for daylight saving
+time.
+.SH NOTES
+For areas with more than two types of local time,
+you may need to use local standard time in the
+.B AT
+field of the earliest transition time's rule to ensure that
+the earliest transition time recorded in the compiled file is correct.
+.PP
+If,
+for a particular zone,
+a clock advance caused by the start of daylight saving
+coincides with and is equal to
+a clock retreat caused by a change in UT offset,
+.IR zic
+produces a single transition to daylight saving at the new UT offset
+(without any change in wall clock time).
+To get separate transitions
+use multiple zone continuation lines
+specifying transition instants using universal time.
+.PP
+Time stamps well before the Big Bang are silently omitted from the output.
+This works around bugs in software that mishandles large negative time
+stamps.  Call it sour grapes, but pre-Big-Bang time stamps are
+physically suspect anyway.  The pre-Big-Bang cutoff time is
+approximate and may change in future versions.
+.SH FILES
+.ta \w'/usr/share/zoneinfo\0\0'u
+/etc/localtime	default local time zone file
+/usr/share/zoneinfo	default time zone information directory
+.SH "SEE ALSO"
+newctime(3), tzfile(5), zdump(8)
+.\" This file is in the public domain, so clarified as of
+.\" 2009-05-17 by Arthur David Olson.
diff --git a/zic.8.txt b/zic.8.txt
new file mode 100644
index 000000000000..fc91cb29a961
--- /dev/null
+++ b/zic.8.txt
@@ -0,0 +1,372 @@
+ZIC(8)                      System Manager's Manual                     ZIC(8)
+
+NAME
+       zic - time zone compiler
+
+SYNOPSIS
+       zic [ option ... ] [ filename ... ]
+
+DESCRIPTION
+       Zic reads text from the file(s) named on the command line and creates
+       the time conversion information files specified in this input.  If a
+       filename is "-", the standard input is read.
+
+       These options are available:
+
+       --version
+              Output version information and exit.
+
+       -d directory
+              Create time conversion information files in the named directory
+              rather than in the standard directory named below.
+
+       -l timezone
+              Use the given time zone as local time.  Zic will act as if the
+              input contained a link line of the form
+
+                   Link timezone       localtime
+
+       -p timezone
+              Use the given time zone's rules when handling POSIX-format time
+              zone environment variables.  Zic will act as if the input
+              contained a link line of the form
+
+                   Link timezone       posixrules
+
+       -t file
+              When creating local time information, put the configuration link
+              in the named file rather than in the standard location.
+
+       -L leapsecondfilename
+              Read leap second information from the file with the given name.
+              If this option is not used, no leap second information appears
+              in output files.
+
+       -v     Be more verbose, and complain about the following situations:
+
+              The input specifies a link to a link.
+
+              A year that appears in a data file is outside the range of years
+              representable by time(2) values.
+
+              A time of 24:00 or more appears in the input.  Pre-1998 versions
+              of zic prohibit 24:00, and pre-2007 versions prohibit times
+              greater than 24:00.
+
+              A rule goes past the start or end of the month.  Pre-2004
+              versions of zic prohibit this.
+
+              The output file does not contain all the information about the
+              long-term future of a zone, because the future cannot be
+              summarized as an extended POSIX TZ string.  For example, as of
+              2013 this problem occurs for Iran's daylight-saving rules for
+              the predicted future, as these rules are based on the Iranian
+              calendar, which cannot be represented.
+
+              The output contains data that may not be handled properly by
+              client code designed for older zic output formats.  These
+              compatibility issues affect only time stamps before 1970 or
+              after the start of 2038.
+
+              A time zone abbreviation has fewer than 3 characters.  POSIX
+              requires at least 3.
+
+              An output file name contains a byte that is not an ASCII letter,
+              "-", "/", or "_"; or it contains a file name component that
+              contains more than 14 bytes or that starts with "-".
+
+       -s     Limit time values stored in output files to values that are the
+              same whether they're taken to be signed or unsigned.  You can
+              use this option to generate SVVS-compatible files.
+
+       Input files should be text files, that is, they should be a series of
+       zero or more lines, each ending in a newline byte and containing at
+       most 511 bytes, and without any NUL bytes.  The input text's encoding
+       is typically UTF-8 or ASCII; it should have a unibyte representation
+       for the POSIX Portable Character Set (PPCS) <http://pubs.opengroup.org/
+       onlinepubs/9699919799/basedefs/V1_chap06.html> and the encoding's non-
+       unibyte characters should consist entirely of non-PPCS bytes.  Non-PPCS
+       characters typically occur only in comments: although output file names
+       and time zone abbreviations can contain nearly any character, other
+       software will work better if these are limited to the restricted syntax
+       described under the -v option.
+
+       Input lines are made up of fields.  Fields are separated from one
+       another by one or more white space characters.  The white space
+       characters are space, form feed, carriage return, newline, tab, and
+       vertical tab.  Leading and trailing white space on input lines is
+       ignored.  An unquoted sharp character (#) in the input introduces a
+       comment which extends to the end of the line the sharp character
+       appears on.  White space characters and sharp characters may be
+       enclosed in double quotes (") if they're to be used as part of a field.
+       Any line that is blank (after comment stripping) is ignored.  Non-blank
+       lines are expected to be of one of three types: rule lines, zone lines,
+       and link lines.
+
+       Names must be in English and are case insensitive.  They appear in
+       several contexts, and include month and weekday names and keywords such
+       as maximum, only, Rolling, and Zone.  A name can be abbreviated by
+       omitting all but an initial prefix; any abbreviation must be
+       unambiguous in context.
+
+       A rule line has the form
+
+            Rule  NAME  FROM  TO    TYPE  IN   ON       AT     SAVE   LETTER/S
+
+       For example:
+
+            Rule  US    1967  1973  -     Apr  lastSun  2:00s  1:00d  D
+
+       The fields that make up a rule line are:
+
+       NAME    Gives the (arbitrary) name of the set of rules this rule is
+               part of.
+
+       FROM    Gives the first year in which the rule applies.  Any signed
+               integer year can be supplied; the proleptic Gregorian calendar
+               is assumed, with year 0 preceding year 1.  The word minimum (or
+               an abbreviation) means the indefinite past.  The word maximum
+               (or an abbreviation) means the indefinite future.  Rules can
+               describe times that are not representable as time values, with
+               the unrepresentable times ignored; this allows rules to be
+               portable among hosts with differing time value types.
+
+       TO      Gives the final year in which the rule applies.  In addition to
+               minimum and maximum (as above), the word only (or an
+               abbreviation) may be used to repeat the value of the FROM
+               field.
+
+       TYPE    should be "-" and is present for compatibility with older
+               versions of zic in which it could contain year types.
+
+       IN      Names the month in which the rule takes effect.  Month names
+               may be abbreviated.
+
+       ON      Gives the day on which the rule takes effect.  Recognized forms
+               include:
+
+                    5        the fifth of the month
+                    lastSun  the last Sunday in the month
+                    lastMon  the last Monday in the month
+                    Sun>=8   first Sunday on or after the eighth
+                    Sun<=25  last Sunday on or before the 25th
+
+               A weekday name (e.g., Sunday) or a weekday name preceded by
+               "last" (e.g., lastSunday) may be abbreviated or spelled out in
+               full.  Note that there must be no spaces within the ON field.
+
+       AT      Gives the time of day at which the rule takes effect.
+               Recognized forms include:
+
+                    2            time in hours
+                    2:00         time in hours and minutes
+                    01:28:14     time in hours, minutes, and seconds
+                    00:19:32.13  time with fractional seconds
+                    15:00        24-hour format time (for times after noon)
+                    260:00       260 hours after 00:00
+                    -2:30        2.5 hours before 00:00
+                    -            equivalent to 0
+
+               where hour 0 is midnight at the start of the day, and hour 24
+               is midnight at the end of the day.  Although zic rounds times
+               to the nearest integer second (breaking ties to the even
+               integer), the fractions may be useful to other applications
+               requiring greater precision.  The source format does not
+               specify any maximum precision.  Any of these forms may be
+               followed by the letter w if the given time is local "wall
+               clock" time, s if the given time is local "standard" time, or u
+               (or g or z) if the given time is universal time; in the absence
+               of an indicator, wall clock time is assumed.  The intent is
+               that a rule line describes the instants when a clock/calendar
+               set to the type of time specified in the AT field would show
+               the specified date and time of day.
+
+       SAVE    Gives the amount of time to be added to local standard time
+               when the rule is in effect, and whether the resulting time is
+               standard or daylight saving.  This field has the same format as
+               the AT field except with a different set of suffix letters: s
+               for standard time and d for daylight saving time.  The suffix
+               letter is typically omitted, and defaults to s if the offset is
+               zero and to d otherwise.  Negative offsets are allowed; in
+               Ireland, for example, daylight saving time is observed in
+               winter and has a negative offset relative to Irish Standard
+               Time.  The offset is merely added to standard time; for
+               example, zic does not distinguish a 10:30 standard time plus an
+               0:30 SAVE from a 10:00 standard time plus a 1:00 SAVE.
+
+       LETTER/S
+               Gives the "variable part" (for example, the "S" or "D" in "EST"
+               or "EDT") of time zone abbreviations to be used when this rule
+               is in effect.  If this field is "-", the variable part is null.
+
+       A zone line has the form
+
+            Zone  NAME        GMTOFF  RULES   FORMAT  [UNTIL]
+
+       For example:
+
+            Zone  Asia/Amman  2:00    Jordan  EE%sT   2017 Oct 27 01:00
+
+       The fields that make up a zone line are:
+
+       NAME  The name of the time zone.  This is the name used in creating the
+             time conversion information file for the zone.  It should not
+             contain a file name component "." or ".."; a file name component
+             is a maximal substring that does not contain "/".
+
+       GMTOFF
+             The amount of time to add to UT to get standard time in this
+             zone.  This field has the same format as the AT and SAVE fields
+             of rule lines; begin the field with a minus sign if time must be
+             subtracted from UT.
+
+       RULES The name of the rules that apply in the time zone or,
+             alternatively, a field in the same format as a rule-line SAVE
+             column, giving of the amount of time to be added to local
+             standard time effect, and whether the resulting time is standard
+             or daylight saving.  If this field is - then standard time always
+             applies in the time zone.  When an amount of time is given, only
+             the sum of standard time and this amount matters.
+
+       FORMAT
+             The format for time zone abbreviations in this time zone.  The
+             pair of characters %s is used to show where the "variable part"
+             of the time zone abbreviation goes.  Alternatively, a format can
+             use the pair of characters %z to stand for the UT offset in the
+             form +-hh, +-hhmm, or +-hhmmss, using the shortest form that does
+             not lose information, where hh, mm, and ss are the hours,
+             minutes, and seconds east (+) or west (-) of UT.  Alternatively,
+             a slash (/) separates standard and daylight abbreviations.  To
+             conform to POSIX, a time zone abbreviation should contain only
+             alphanumeric ASCII characters, "+" and "-".
+
+       UNTIL The time at which the UT offset or the rule(s) change for a
+             location.  It takes the form of YEAR [MONTH [DAY [TIME]]].  If
+             this is specified, the time zone information is generated from
+             the given UT offset and rule change until the time specified,
+             which is interpreted using the rules in effect just before the
+             transition.  The month, day, and time of day have the same format
+             as the IN, ON, and AT fields of a rule; trailing fields can be
+             omitted, and default to the earliest possible value for the
+             missing fields.
+
+             The next line must be a "continuation" line; this has the same
+             form as a zone line except that the string "Zone" and the name
+             are omitted, as the continuation line will place information
+             starting at the time specified as the "until" information in the
+             previous line in the file used by the previous line.
+             Continuation lines may contain "until" information, just as zone
+             lines do, indicating that the next line is a further
+             continuation.
+
+       If a zone changes at the same instant that a rule would otherwise take
+       effect in the earlier zone or continuation line, the rule is ignored.
+       In a single zone it is an error if two rules take effect at the same
+       instant, or if two zone changes take effect at the same instant.
+
+       A link line has the form
+
+            Link  TARGET           LINK-NAME
+
+       For example:
+
+            Link  Europe/Istanbul  Asia/Istanbul
+
+       The TARGET field should appear as the NAME field in some zone line.
+       The LINK-NAME field is used as an alternative name for that zone; it
+       has the same syntax as a zone line's NAME field.
+
+       Except for continuation lines, lines may appear in any order in the
+       input.  However, the behavior is unspecified if multiple zone or link
+       lines define the same name, or if the source of one link line is the
+       target of another.
+
+       Lines in the file that describes leap seconds have the following form:
+
+            Leap  YEAR  MONTH  DAY  HH:MM:SS  CORR  R/S
+
+       For example:
+
+            Leap  2016  Dec    31   23:59:60  +     S
+
+       The YEAR, MONTH, DAY, and HH:MM:SS fields tell when the leap second
+       happened.  The CORR field should be "+" if a second was added or "-" if
+       a second was skipped.  The R/S field should be (an abbreviation of)
+       "Stationary" if the leap second time given by the other fields should
+       be interpreted as UTC or (an abbreviation of) "Rolling" if the leap
+       second time given by the other fields should be interpreted as local
+       wall clock time.
+
+EXTENDED EXAMPLE
+       Here is an extended example of zic input, intended to illustrate many
+       of its features.  In this example, the EU rules are for the European
+       Union and for its predecessor organization, the European Communities.
+
+         # Rule  NAME  FROM  TO    TYPE  IN   ON       AT    SAVE  LETTER/S
+         Rule    Swiss 1941  1942  -     May  Mon>=1   1:00  1:00  S
+         Rule    Swiss 1941  1942  -     Oct  Mon>=1   2:00  0     -
+         Rule    EU    1977  1980  -     Apr  Sun>=1   1:00u 1:00  S
+         Rule    EU    1977  only  -     Sep  lastSun  1:00u 0     -
+         Rule    EU    1978  only  -     Oct   1       1:00u 0     -
+         Rule    EU    1979  1995  -     Sep  lastSun  1:00u 0     -
+         Rule    EU    1981  max   -     Mar  lastSun  1:00u 1:00  S
+         Rule    EU    1996  max   -     Oct  lastSun  1:00u 0     -
+
+         # Zone  NAME           GMTOFF  RULES    FORMAT  [UNTIL]
+         Zone    Europe/Zurich  0:34:08 -        LMT     1853 Jul 16
+                                0:29:46 -        BMT     1894 Jun
+                                1:00    Swiss    CE%sT   1981
+                                1:00    EU       CE%sT
+
+         Link    Europe/Zurich  Europe/Vaduz
+
+       In this example, the zone is named Europe/Zurich but it has an alias as
+       Europe/Vaduz.  This example says that Zurich was 34 minutes and 8
+       seconds east of UT until 1853-07-16 at 00:00, when the legal offset was
+       changed to 7o26'22.50''; although this works out to 0:29:45.50, the
+       input format cannot represent fractional seconds so it is rounded here.
+       After 1894-06-01 at 00:00 the UT offset became one hour and Swiss
+       daylight saving rules (defined with lines beginning with "Rule Swiss")
+       apply.  From 1981 to the present, EU daylight saving rules have
+       applied, and the UTC offset has remained at one hour.
+
+       In 1941 and 1942, daylight saving time applied from the first Monday in
+       May at 01:00 to the first Monday in October at 02:00.  The pre-1981 EU
+       daylight-saving rules have no effect here, but are included for
+       completeness.  Since 1981, daylight saving has begun on the last Sunday
+       in March at 01:00 UTC.  Until 1995 it ended the last Sunday in
+       September at 01:00 UTC, but this changed to the last Sunday in October
+       starting in 1996.
+
+       For purposes of display, "LMT" and "BMT" were initially used,
+       respectively.  Since Swiss rules and later EU rules were applied, the
+       display name for the time zone has been CET for standard time and CEST
+       for daylight saving time.
+
+NOTES
+       For areas with more than two types of local time, you may need to use
+       local standard time in the AT field of the earliest transition time's
+       rule to ensure that the earliest transition time recorded in the
+       compiled file is correct.
+
+       If, for a particular zone, a clock advance caused by the start of
+       daylight saving coincides with and is equal to a clock retreat caused
+       by a change in UT offset, zic produces a single transition to daylight
+       saving at the new UT offset (without any change in wall clock time).
+       To get separate transitions use multiple zone continuation lines
+       specifying transition instants using universal time.
+
+       Time stamps well before the Big Bang are silently omitted from the
+       output.  This works around bugs in software that mishandles large
+       negative time stamps.  Call it sour grapes, but pre-Big-Bang time
+       stamps are physically suspect anyway.  The pre-Big-Bang cutoff time is
+       approximate and may change in future versions.
+
+FILES
+       /etc/localtime       default local time zone file
+       /usr/share/zoneinfo  default time zone information directory
+
+SEE ALSO
+       newctime(3), tzfile(5), zdump(8)
+
+                                                                        ZIC(8)
diff --git a/zic.c b/zic.c
new file mode 100644
index 000000000000..31f10923c100
--- /dev/null
+++ b/zic.c
@@ -0,0 +1,3286 @@
+/*
+** This file is in the public domain, so clarified as of
+** 2006-07-17 by Arthur David Olson.
+*/
+
+#include "version.h"
+#include "private.h"
+#include "tzfile.h"
+
+#include <fcntl.h>
+#include <locale.h>
+#include <stdarg.h>
+#include <stddef.h>
+#include <stdio.h>
+
+#define	ZIC_VERSION_PRE_2013 '2'
+#define	ZIC_VERSION	'3'
+
+typedef int_fast64_t	zic_t;
+#define ZIC_MIN INT_FAST64_MIN
+#define ZIC_MAX INT_FAST64_MAX
+#define PRIdZIC PRIdFAST64
+#define SCNdZIC SCNdFAST64
+
+#ifndef ZIC_MAX_ABBR_LEN_WO_WARN
+#define ZIC_MAX_ABBR_LEN_WO_WARN	6
+#endif /* !defined ZIC_MAX_ABBR_LEN_WO_WARN */
+
+#ifdef HAVE_DIRECT_H
+# include <direct.h>
+# include <io.h>
+# undef mkdir
+# define mkdir(name, mode) _mkdir(name)
+#endif
+
+#if HAVE_SYS_STAT_H
+#include <sys/stat.h>
+#endif
+#ifdef S_IRUSR
+#define MKDIR_UMASK (S_IRUSR|S_IWUSR|S_IXUSR|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH)
+#else
+#define MKDIR_UMASK 0755
+#endif
+/* Port to native MS-Windows and to ancient UNIX.  */
+#if !defined S_ISDIR && defined S_IFDIR && defined S_IFMT
+# define S_ISDIR(mode) (((mode) & S_IFMT) == S_IFDIR)
+#endif
+
+#if HAVE_SYS_WAIT_H
+#include <sys/wait.h>	/* for WIFEXITED and WEXITSTATUS */
+#endif /* HAVE_SYS_WAIT_H */
+
+#ifndef WIFEXITED
+#define WIFEXITED(status)	(((status) & 0xff) == 0)
+#endif /* !defined WIFEXITED */
+#ifndef WEXITSTATUS
+#define WEXITSTATUS(status)	(((status) >> 8) & 0xff)
+#endif /* !defined WEXITSTATUS */
+
+/* The maximum ptrdiff_t value, for pre-C99 platforms.  */
+#ifndef PTRDIFF_MAX
+static ptrdiff_t const PTRDIFF_MAX = MAXVAL(ptrdiff_t, TYPE_BIT(ptrdiff_t));
+#endif
+
+/* The type for line numbers.  Use PRIdMAX to format them; formerly
+   there was also "#define PRIdLINENO PRIdMAX" and formats used
+   PRIdLINENO, but xgettext cannot grok that.  */
+typedef intmax_t lineno;
+
+struct rule {
+	const char *	r_filename;
+	lineno		r_linenum;
+	const char *	r_name;
+
+	zic_t		r_loyear;	/* for example, 1986 */
+	zic_t		r_hiyear;	/* for example, 1986 */
+	const char *	r_yrtype;
+	bool		r_lowasnum;
+	bool		r_hiwasnum;
+
+	int		r_month;	/* 0..11 */
+
+	int		r_dycode;	/* see below */
+	int		r_dayofmonth;
+	int		r_wday;
+
+	zic_t		r_tod;		/* time from midnight */
+	bool		r_todisstd;	/* above is standard time if 1 */
+					/* or wall clock time if 0 */
+	bool		r_todisgmt;	/* above is GMT if 1 */
+					/* or local time if 0 */
+	bool		r_isdst;	/* is this daylight saving time? */
+	zic_t		r_stdoff;	/* offset from default time (which is
+					   usually standard time) */
+	const char *	r_abbrvar;	/* variable part of abbreviation */
+
+	bool		r_todo;		/* a rule to do (used in outzone) */
+	zic_t		r_temp;		/* used in outzone */
+};
+
+/*
+**	r_dycode		r_dayofmonth	r_wday
+*/
+
+#define DC_DOM		0	/* 1..31 */	/* unused */
+#define DC_DOWGEQ	1	/* 1..31 */	/* 0..6 (Sun..Sat) */
+#define DC_DOWLEQ	2	/* 1..31 */	/* 0..6 (Sun..Sat) */
+
+struct zone {
+	const char *	z_filename;
+	lineno		z_linenum;
+
+	const char *	z_name;
+	zic_t		z_gmtoff;
+	char *		z_rule;
+	const char *	z_format;
+	char		z_format_specifier;
+
+	bool		z_isdst;
+	zic_t		z_stdoff;
+
+	struct rule *	z_rules;
+	ptrdiff_t	z_nrules;
+
+	struct rule	z_untilrule;
+	zic_t		z_untiltime;
+};
+
+#if !HAVE_POSIX_DECLS
+extern int	getopt(int argc, char * const argv[],
+			const char * options);
+extern int	link(const char * fromname, const char * toname);
+extern char *	optarg;
+extern int	optind;
+#endif
+
+#if ! HAVE_LINK
+# define link(from, to) (errno = ENOTSUP, -1)
+#endif
+#if ! HAVE_SYMLINK
+# define readlink(file, buf, size) (errno = ENOTSUP, -1)
+# define symlink(from, to) (errno = ENOTSUP, -1)
+# define S_ISLNK(m) 0
+#endif
+#ifndef AT_SYMLINK_FOLLOW
+# define linkat(fromdir, from, todir, to, flag) \
+    (itssymlink(from) ? (errno = ENOTSUP, -1) : link(from, to))
+#endif
+
+static void	addtt(zic_t starttime, int type);
+static int	addtype(zic_t, char const *, bool, bool, bool);
+static void	leapadd(zic_t, bool, int, int);
+static void	adjleap(void);
+static void	associate(void);
+static void	dolink(const char *, const char *, bool);
+static char **	getfields(char * buf);
+static zic_t	gethms(const char * string, const char * errstring,
+		       bool);
+static zic_t	getstdoff(char *, bool *);
+static void	infile(const char * filename);
+static void	inleap(char ** fields, int nfields);
+static void	inlink(char ** fields, int nfields);
+static void	inrule(char ** fields, int nfields);
+static bool	inzcont(char ** fields, int nfields);
+static bool	inzone(char ** fields, int nfields);
+static bool	inzsub(char **, int, bool);
+static bool	itsdir(char const *);
+static bool	itssymlink(char const *);
+static bool	is_alpha(char a);
+static char	lowerit(char);
+static void	mkdirs(char const *, bool);
+static void	newabbr(const char * abbr);
+static zic_t	oadd(zic_t t1, zic_t t2);
+static void	outzone(const struct zone * zp, ptrdiff_t ntzones);
+static zic_t	rpytime(const struct rule * rp, zic_t wantedy);
+static void	rulesub(struct rule * rp,
+			const char * loyearp, const char * hiyearp,
+			const char * typep, const char * monthp,
+			const char * dayp, const char * timep);
+static zic_t	tadd(zic_t t1, zic_t t2);
+static bool	yearistype(zic_t year, const char * type);
+
+/* Bound on length of what %z can expand to.  */
+enum { PERCENT_Z_LEN_BOUND = sizeof "+995959" - 1 };
+
+/* If true, work around a bug in Qt 5.6.1 and earlier, which mishandles
+   tz binary files whose POSIX-TZ-style strings contain '<'; see
+   QTBUG-53071 <https://bugreports.qt.io/browse/QTBUG-53071>.  This
+   workaround will no longer be needed when Qt 5.6.1 and earlier are
+   obsolete, say in the year 2021.  */
+enum { WORK_AROUND_QTBUG_53071 = true };
+
+static int		charcnt;
+static bool		errors;
+static bool		warnings;
+static const char *	filename;
+static int		leapcnt;
+static bool		leapseen;
+static zic_t		leapminyear;
+static zic_t		leapmaxyear;
+static lineno		linenum;
+static int		max_abbrvar_len = PERCENT_Z_LEN_BOUND;
+static int		max_format_len;
+static zic_t		max_year;
+static zic_t		min_year;
+static bool		noise;
+static const char *	rfilename;
+static lineno		rlinenum;
+static const char *	progname;
+static ptrdiff_t	timecnt;
+static ptrdiff_t	timecnt_alloc;
+static int		typecnt;
+
+/*
+** Line codes.
+*/
+
+#define LC_RULE		0
+#define LC_ZONE		1
+#define LC_LINK		2
+#define LC_LEAP		3
+
+/*
+** Which fields are which on a Zone line.
+*/
+
+#define ZF_NAME		1
+#define ZF_GMTOFF	2
+#define ZF_RULE		3
+#define ZF_FORMAT	4
+#define ZF_TILYEAR	5
+#define ZF_TILMONTH	6
+#define ZF_TILDAY	7
+#define ZF_TILTIME	8
+#define ZONE_MINFIELDS	5
+#define ZONE_MAXFIELDS	9
+
+/*
+** Which fields are which on a Zone continuation line.
+*/
+
+#define ZFC_GMTOFF	0
+#define ZFC_RULE	1
+#define ZFC_FORMAT	2
+#define ZFC_TILYEAR	3
+#define ZFC_TILMONTH	4
+#define ZFC_TILDAY	5
+#define ZFC_TILTIME	6
+#define ZONEC_MINFIELDS	3
+#define ZONEC_MAXFIELDS	7
+
+/*
+** Which files are which on a Rule line.
+*/
+
+#define RF_NAME		1
+#define RF_LOYEAR	2
+#define RF_HIYEAR	3
+#define RF_COMMAND	4
+#define RF_MONTH	5
+#define RF_DAY		6
+#define RF_TOD		7
+#define RF_STDOFF	8
+#define RF_ABBRVAR	9
+#define RULE_FIELDS	10
+
+/*
+** Which fields are which on a Link line.
+*/
+
+#define LF_FROM		1
+#define LF_TO		2
+#define LINK_FIELDS	3
+
+/*
+** Which fields are which on a Leap line.
+*/
+
+#define LP_YEAR		1
+#define LP_MONTH	2
+#define LP_DAY		3
+#define LP_TIME		4
+#define LP_CORR		5
+#define LP_ROLL		6
+#define LEAP_FIELDS	7
+
+/*
+** Year synonyms.
+*/
+
+#define YR_MINIMUM	0
+#define YR_MAXIMUM	1
+#define YR_ONLY		2
+
+static struct rule *	rules;
+static ptrdiff_t	nrules;	/* number of rules */
+static ptrdiff_t	nrules_alloc;
+
+static struct zone *	zones;
+static ptrdiff_t	nzones;	/* number of zones */
+static ptrdiff_t	nzones_alloc;
+
+struct link {
+	const char *	l_filename;
+	lineno		l_linenum;
+	const char *	l_from;
+	const char *	l_to;
+};
+
+static struct link *	links;
+static ptrdiff_t	nlinks;
+static ptrdiff_t	nlinks_alloc;
+
+struct lookup {
+	const char *	l_word;
+	const int	l_value;
+};
+
+static struct lookup const *	byword(const char * string,
+					const struct lookup * lp);
+
+static struct lookup const zi_line_codes[] = {
+	{ "Rule",	LC_RULE },
+	{ "Zone",	LC_ZONE },
+	{ "Link",	LC_LINK },
+	{ NULL,		0 }
+};
+static struct lookup const leap_line_codes[] = {
+	{ "Leap",	LC_LEAP },
+	{ NULL,		0}
+};
+
+static struct lookup const	mon_names[] = {
+	{ "January",	TM_JANUARY },
+	{ "February",	TM_FEBRUARY },
+	{ "March",	TM_MARCH },
+	{ "April",	TM_APRIL },
+	{ "May",	TM_MAY },
+	{ "June",	TM_JUNE },
+	{ "July",	TM_JULY },
+	{ "August",	TM_AUGUST },
+	{ "September",	TM_SEPTEMBER },
+	{ "October",	TM_OCTOBER },
+	{ "November",	TM_NOVEMBER },
+	{ "December",	TM_DECEMBER },
+	{ NULL,		0 }
+};
+
+static struct lookup const	wday_names[] = {
+	{ "Sunday",	TM_SUNDAY },
+	{ "Monday",	TM_MONDAY },
+	{ "Tuesday",	TM_TUESDAY },
+	{ "Wednesday",	TM_WEDNESDAY },
+	{ "Thursday",	TM_THURSDAY },
+	{ "Friday",	TM_FRIDAY },
+	{ "Saturday",	TM_SATURDAY },
+	{ NULL,		0 }
+};
+
+static struct lookup const	lasts[] = {
+	{ "last-Sunday",	TM_SUNDAY },
+	{ "last-Monday",	TM_MONDAY },
+	{ "last-Tuesday",	TM_TUESDAY },
+	{ "last-Wednesday",	TM_WEDNESDAY },
+	{ "last-Thursday",	TM_THURSDAY },
+	{ "last-Friday",	TM_FRIDAY },
+	{ "last-Saturday",	TM_SATURDAY },
+	{ NULL,			0 }
+};
+
+static struct lookup const	begin_years[] = {
+	{ "minimum",	YR_MINIMUM },
+	{ "maximum",	YR_MAXIMUM },
+	{ NULL,		0 }
+};
+
+static struct lookup const	end_years[] = {
+	{ "minimum",	YR_MINIMUM },
+	{ "maximum",	YR_MAXIMUM },
+	{ "only",	YR_ONLY },
+	{ NULL,		0 }
+};
+
+static struct lookup const	leap_types[] = {
+	{ "Rolling",	true },
+	{ "Stationary",	false },
+	{ NULL,		0 }
+};
+
+static const int	len_months[2][MONSPERYEAR] = {
+	{ 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 },
+	{ 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }
+};
+
+static const int	len_years[2] = {
+	DAYSPERNYEAR, DAYSPERLYEAR
+};
+
+static struct attype {
+	zic_t		at;
+	bool		dontmerge;
+	unsigned char	type;
+} *			attypes;
+static zic_t		gmtoffs[TZ_MAX_TYPES];
+static char		isdsts[TZ_MAX_TYPES];
+static unsigned char	abbrinds[TZ_MAX_TYPES];
+static bool		ttisstds[TZ_MAX_TYPES];
+static bool		ttisgmts[TZ_MAX_TYPES];
+static char		chars[TZ_MAX_CHARS];
+static zic_t		trans[TZ_MAX_LEAPS];
+static zic_t		corr[TZ_MAX_LEAPS];
+static char		roll[TZ_MAX_LEAPS];
+
+/*
+** Memory allocation.
+*/
+
+static _Noreturn void
+memory_exhausted(const char *msg)
+{
+	fprintf(stderr, _("%s: Memory exhausted: %s\n"), progname, msg);
+	exit(EXIT_FAILURE);
+}
+
+static ATTRIBUTE_PURE size_t
+size_product(size_t nitems, size_t itemsize)
+{
+	if (SIZE_MAX / itemsize < nitems)
+		memory_exhausted(_("size overflow"));
+	return nitems * itemsize;
+}
+
+#if !HAVE_STRDUP
+static char *
+strdup(char const *str)
+{
+  char *result = malloc(strlen(str) + 1);
+  return result ? strcpy(result, str) : result;
+}
+#endif
+
+static void *
+memcheck(void *ptr)
+{
+	if (ptr == NULL)
+		memory_exhausted(strerror(errno));
+	return ptr;
+}
+
+static void * ATTRIBUTE_MALLOC
+emalloc(size_t size)
+{
+  return memcheck(malloc(size));
+}
+
+static void *
+erealloc(void *ptr, size_t size)
+{
+  return memcheck(realloc(ptr, size));
+}
+
+static char * ATTRIBUTE_MALLOC
+ecpyalloc (char const *str)
+{
+  return memcheck(strdup(str));
+}
+
+static void *
+growalloc(void *ptr, size_t itemsize, ptrdiff_t nitems, ptrdiff_t *nitems_alloc)
+{
+	if (nitems < *nitems_alloc)
+		return ptr;
+	else {
+		ptrdiff_t nitems_max = PTRDIFF_MAX - WORK_AROUND_QTBUG_53071;
+		ptrdiff_t amax = nitems_max < SIZE_MAX ? nitems_max : SIZE_MAX;
+		if ((amax - 1) / 3 * 2 < *nitems_alloc)
+			memory_exhausted(_("integer overflow"));
+		*nitems_alloc += (*nitems_alloc >> 1) + 1;
+		return erealloc(ptr, size_product(*nitems_alloc, itemsize));
+	}
+}
+
+/*
+** Error handling.
+*/
+
+static void
+eats(char const *name, lineno num, char const *rname, lineno rnum)
+{
+	filename = name;
+	linenum = num;
+	rfilename = rname;
+	rlinenum = rnum;
+}
+
+static void
+eat(char const *name, lineno num)
+{
+	eats(name, num, NULL, -1);
+}
+
+static void ATTRIBUTE_FORMAT((printf, 1, 0))
+verror(const char *const string, va_list args)
+{
+	/*
+	** Match the format of "cc" to allow sh users to
+	**	zic ... 2>&1 | error -t "*" -v
+	** on BSD systems.
+	*/
+	if (filename)
+	  fprintf(stderr, _("\"%s\", line %"PRIdMAX": "), filename, linenum);
+	vfprintf(stderr, string, args);
+	if (rfilename != NULL)
+		fprintf(stderr, _(" (rule from \"%s\", line %"PRIdMAX")"),
+			rfilename, rlinenum);
+	fprintf(stderr, "\n");
+}
+
+static void ATTRIBUTE_FORMAT((printf, 1, 2))
+error(const char *const string, ...)
+{
+	va_list args;
+	va_start(args, string);
+	verror(string, args);
+	va_end(args);
+	errors = true;
+}
+
+static void ATTRIBUTE_FORMAT((printf, 1, 2))
+warning(const char *const string, ...)
+{
+	va_list args;
+	fprintf(stderr, _("warning: "));
+	va_start(args, string);
+	verror(string, args);
+	va_end(args);
+	warnings = true;
+}
+
+static void
+close_file(FILE *stream, char const *dir, char const *name)
+{
+  char const *e = (ferror(stream) ? _("I/O error")
+		   : fclose(stream) != 0 ? strerror(errno) : NULL);
+  if (e) {
+    fprintf(stderr, "%s: %s%s%s%s%s\n", progname,
+	    dir ? dir : "", dir ? "/" : "",
+	    name ? name : "", name ? ": " : "",
+	    e);
+    exit(EXIT_FAILURE);
+  }
+}
+
+static _Noreturn void
+usage(FILE *stream, int status)
+{
+  fprintf(stream,
+	  _("%s: usage is %s [ --version ] [ --help ] [ -v ] \\\n"
+	    "\t[ -l localtime ] [ -p posixrules ] [ -d directory ] \\\n"
+	    "\t[ -t localtime-link ] [ -L leapseconds ] [ filename ... ]\n\n"
+	    "Report bugs to %s.\n"),
+	  progname, progname, REPORT_BUGS_TO);
+  if (status == EXIT_SUCCESS)
+    close_file(stream, NULL, NULL);
+  exit(status);
+}
+
+/* Change the working directory to DIR, possibly creating DIR and its
+   ancestors.  After this is done, all files are accessed with names
+   relative to DIR.  */
+static void
+change_directory (char const *dir)
+{
+  if (chdir(dir) != 0) {
+    int chdir_errno = errno;
+    if (chdir_errno == ENOENT) {
+      mkdirs(dir, false);
+      chdir_errno = chdir(dir) == 0 ? 0 : errno;
+    }
+    if (chdir_errno != 0) {
+      fprintf(stderr, _("%s: Can't chdir to %s: %s\n"),
+	      progname, dir, strerror(chdir_errno));
+      exit(EXIT_FAILURE);
+    }
+  }
+}
+
+static const char *	psxrules;
+static const char *	lcltime;
+static const char *	directory;
+static const char *	leapsec;
+static const char *	tzdefault;
+static const char *	yitcommand;
+
+int
+main(int argc, char **argv)
+{
+	register int c, k;
+	register ptrdiff_t i, j;
+
+#ifdef S_IWGRP
+	umask(umask(S_IWGRP | S_IWOTH) | (S_IWGRP | S_IWOTH));
+#endif
+#if HAVE_GETTEXT
+	setlocale(LC_ALL, "");
+#ifdef TZ_DOMAINDIR
+	bindtextdomain(TZ_DOMAIN, TZ_DOMAINDIR);
+#endif /* defined TEXTDOMAINDIR */
+	textdomain(TZ_DOMAIN);
+#endif /* HAVE_GETTEXT */
+	progname = argv[0];
+	if (TYPE_BIT(zic_t) < 64) {
+		fprintf(stderr, "%s: %s\n", progname,
+			_("wild compilation-time specification of zic_t"));
+		return EXIT_FAILURE;
+	}
+	for (k = 1; k < argc; k++)
+		if (strcmp(argv[k], "--version") == 0) {
+			printf("zic %s%s\n", PKGVERSION, TZVERSION);
+			close_file(stdout, NULL, NULL);
+			return EXIT_SUCCESS;
+		} else if (strcmp(argv[k], "--help") == 0) {
+			usage(stdout, EXIT_SUCCESS);
+		}
+	while ((c = getopt(argc, argv, "d:l:L:p:st:vy:")) != EOF && c != -1)
+		switch (c) {
+			default:
+				usage(stderr, EXIT_FAILURE);
+			case 'd':
+				if (directory == NULL)
+					directory = optarg;
+				else {
+					fprintf(stderr,
+_("%s: More than one -d option specified\n"),
+						progname);
+					return EXIT_FAILURE;
+				}
+				break;
+			case 'l':
+				if (lcltime == NULL)
+					lcltime = optarg;
+				else {
+					fprintf(stderr,
+_("%s: More than one -l option specified\n"),
+						progname);
+					return EXIT_FAILURE;
+				}
+				break;
+			case 'p':
+				if (psxrules == NULL)
+					psxrules = optarg;
+				else {
+					fprintf(stderr,
+_("%s: More than one -p option specified\n"),
+						progname);
+					return EXIT_FAILURE;
+				}
+				break;
+			case 't':
+				if (tzdefault != NULL) {
+				  fprintf(stderr,
+					  _("%s: More than one -t option"
+					    " specified\n"),
+					  progname);
+				  return EXIT_FAILURE;
+				}
+				tzdefault = optarg;
+				break;
+			case 'y':
+				if (yitcommand == NULL) {
+					warning(_("-y is obsolescent"));
+					yitcommand = optarg;
+				} else {
+					fprintf(stderr,
+_("%s: More than one -y option specified\n"),
+						progname);
+					return EXIT_FAILURE;
+				}
+				break;
+			case 'L':
+				if (leapsec == NULL)
+					leapsec = optarg;
+				else {
+					fprintf(stderr,
+_("%s: More than one -L option specified\n"),
+						progname);
+					return EXIT_FAILURE;
+				}
+				break;
+			case 'v':
+				noise = true;
+				break;
+			case 's':
+				warning(_("-s ignored"));
+				break;
+		}
+	if (optind == argc - 1 && strcmp(argv[optind], "=") == 0)
+		usage(stderr, EXIT_FAILURE);	/* usage message by request */
+	if (directory == NULL)
+		directory = TZDIR;
+	if (tzdefault == NULL)
+		tzdefault = TZDEFAULT;
+	if (yitcommand == NULL)
+		yitcommand = "yearistype";
+
+	if (optind < argc && leapsec != NULL) {
+		infile(leapsec);
+		adjleap();
+	}
+
+	for (k = optind; k < argc; k++)
+		infile(argv[k]);
+	if (errors)
+		return EXIT_FAILURE;
+	associate();
+	change_directory(directory);
+	for (i = 0; i < nzones; i = j) {
+		/*
+		** Find the next non-continuation zone entry.
+		*/
+		for (j = i + 1; j < nzones && zones[j].z_name == NULL; ++j)
+			continue;
+		outzone(&zones[i], j - i);
+	}
+	/*
+	** Make links.
+	*/
+	for (i = 0; i < nlinks; ++i) {
+		eat(links[i].l_filename, links[i].l_linenum);
+		dolink(links[i].l_from, links[i].l_to, false);
+		if (noise)
+			for (j = 0; j < nlinks; ++j)
+				if (strcmp(links[i].l_to,
+					links[j].l_from) == 0)
+						warning(_("link to link"));
+	}
+	if (lcltime != NULL) {
+		eat(_("command line"), 1);
+		dolink(lcltime, tzdefault, true);
+	}
+	if (psxrules != NULL) {
+		eat(_("command line"), 1);
+		dolink(psxrules, TZDEFRULES, true);
+	}
+	if (warnings && (ferror(stderr) || fclose(stderr) != 0))
+	  return EXIT_FAILURE;
+	return errors ? EXIT_FAILURE : EXIT_SUCCESS;
+}
+
+static bool
+componentcheck(char const *name, char const *component,
+	       char const *component_end)
+{
+	enum { component_len_max = 14 };
+	ptrdiff_t component_len = component_end - component;
+	if (component_len == 0) {
+	  if (!*name)
+	    error (_("empty file name"));
+	  else
+	    error (_(component == name
+		     ? "file name '%s' begins with '/'"
+		     : *component_end
+		     ? "file name '%s' contains '//'"
+		     : "file name '%s' ends with '/'"),
+		   name);
+	  return false;
+	}
+	if (0 < component_len && component_len <= 2
+	    && component[0] == '.' && component_end[-1] == '.') {
+	  int len = component_len;
+	  error(_("file name '%s' contains '%.*s' component"),
+		name, len, component);
+	  return false;
+	}
+	if (noise) {
+	  if (0 < component_len && component[0] == '-')
+	    warning(_("file name '%s' component contains leading '-'"),
+		    name);
+	  if (component_len_max < component_len)
+	    warning(_("file name '%s' contains overlength component"
+		      " '%.*s...'"),
+		    name, component_len_max, component);
+	}
+	return true;
+}
+
+static bool
+namecheck(const char *name)
+{
+	register char const *cp;
+
+	/* Benign characters in a portable file name.  */
+	static char const benign[] =
+	  "-/_"
+	  "abcdefghijklmnopqrstuvwxyz"
+	  "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
+
+	/* Non-control chars in the POSIX portable character set,
+	   excluding the benign characters.  */
+	static char const printable_and_not_benign[] =
+	  " !\"#$%&'()*+,.0123456789:;<=>?@[\\]^`{|}~";
+
+	register char const *component = name;
+	for (cp = name; *cp; cp++) {
+		unsigned char c = *cp;
+		if (noise && !strchr(benign, c)) {
+			warning((strchr(printable_and_not_benign, c)
+				 ? _("file name '%s' contains byte '%c'")
+				 : _("file name '%s' contains byte '\\%o'")),
+				name, c);
+		}
+		if (c == '/') {
+			if (!componentcheck(name, component, cp))
+			  return false;
+			component = cp + 1;
+		}
+	}
+	return componentcheck(name, component, cp);
+}
+
+/* Create symlink contents suitable for symlinking FROM to TO, as a
+   freshly allocated string.  FROM should be a relative file name, and
+   is relative to the global variable DIRECTORY.  TO can be either
+   relative or absolute.  */
+static char *
+relname(char const *from, char const *to)
+{
+  size_t i, taillen, dotdotetcsize;
+  size_t dir_len = 0, dotdots = 0, linksize = SIZE_MAX;
+  char const *f = from;
+  char *result = NULL;
+  if (*to == '/') {
+    /* Make F absolute too.  */
+    size_t len = strlen(directory);
+    bool needslash = len && directory[len - 1] != '/';
+    linksize = len + needslash + strlen(from) + 1;
+    f = result = emalloc(linksize);
+    strcpy(result, directory);
+    result[len] = '/';
+    strcpy(result + len + needslash, from);
+  }
+  for (i = 0; f[i] && f[i] == to[i]; i++)
+    if (f[i] == '/')
+      dir_len = i + 1;
+  for (; to[i]; i++)
+    dotdots += to[i] == '/' && to[i - 1] != '/';
+  taillen = strlen(f + dir_len);
+  dotdotetcsize = 3 * dotdots + taillen + 1;
+  if (dotdotetcsize <= linksize) {
+    if (!result)
+      result = emalloc(dotdotetcsize);
+    for (i = 0; i < dotdots; i++)
+      memcpy(result + 3 * i, "../", 3);
+    memmove(result + 3 * dotdots, f + dir_len, taillen + 1);
+  }
+  return result;
+}
+
+/* Hard link FROM to TO, following any symbolic links.
+   Return 0 if successful, an error number otherwise.  */
+static int
+hardlinkerr(char const *from, char const *to)
+{
+  int r = linkat(AT_FDCWD, from, AT_FDCWD, to, AT_SYMLINK_FOLLOW);
+  return r == 0 ? 0 : errno;
+}
+
+static void
+dolink(char const *fromfield, char const *tofield, bool staysymlink)
+{
+	bool todirs_made = false;
+	int link_errno;
+
+	/*
+	** We get to be careful here since
+	** there's a fair chance of root running us.
+	*/
+	if (itsdir(fromfield)) {
+		fprintf(stderr, _("%s: link from %s/%s failed: %s\n"),
+			progname, directory, fromfield, strerror(EPERM));
+		exit(EXIT_FAILURE);
+	}
+	if (staysymlink)
+	  staysymlink = itssymlink(tofield);
+	if (remove(tofield) == 0)
+	  todirs_made = true;
+	else if (errno != ENOENT) {
+	  char const *e = strerror(errno);
+	  fprintf(stderr, _("%s: Can't remove %s/%s: %s\n"),
+		  progname, directory, tofield, e);
+	  exit(EXIT_FAILURE);
+	}
+	link_errno = staysymlink ? ENOTSUP : hardlinkerr(fromfield, tofield);
+	if (link_errno == ENOENT && !todirs_made) {
+	  mkdirs(tofield, true);
+	  todirs_made = true;
+	  link_errno = hardlinkerr(fromfield, tofield);
+	}
+	if (link_errno != 0) {
+	  bool absolute = *fromfield == '/';
+	  char *linkalloc = absolute ? NULL : relname(fromfield, tofield);
+	  char const *contents = absolute ? fromfield : linkalloc;
+	  int symlink_errno = symlink(contents, tofield) == 0 ? 0 : errno;
+	  if (!todirs_made
+	      && (symlink_errno == ENOENT || symlink_errno == ENOTSUP)) {
+	    mkdirs(tofield, true);
+	    if (symlink_errno == ENOENT)
+	      symlink_errno = symlink(contents, tofield) == 0 ? 0 : errno;
+	  }
+	  free(linkalloc);
+	  if (symlink_errno == 0) {
+	    if (link_errno != ENOTSUP)
+	      warning(_("symbolic link used because hard link failed: %s"),
+		      strerror(link_errno));
+	  } else {
+	    FILE *fp, *tp;
+	    int c;
+	    fp = fopen(fromfield, "rb");
+	    if (!fp) {
+	      char const *e = strerror(errno);
+	      fprintf(stderr, _("%s: Can't read %s/%s: %s\n"),
+		      progname, directory, fromfield, e);
+	      exit(EXIT_FAILURE);
+	    }
+	    tp = fopen(tofield, "wb");
+	    if (!tp) {
+	      char const *e = strerror(errno);
+	      fprintf(stderr, _("%s: Can't create %s/%s: %s\n"),
+		      progname, directory, tofield, e);
+	      exit(EXIT_FAILURE);
+	    }
+	    while ((c = getc(fp)) != EOF)
+	      putc(c, tp);
+	    close_file(fp, directory, fromfield);
+	    close_file(tp, directory, tofield);
+	    if (link_errno != ENOTSUP)
+	      warning(_("copy used because hard link failed: %s"),
+		      strerror(link_errno));
+	    else if (symlink_errno != ENOTSUP)
+	      warning(_("copy used because symbolic link failed: %s"),
+		      strerror(symlink_errno));
+	  }
+	}
+}
+
+#define TIME_T_BITS_IN_FILE	64
+
+static zic_t const min_time = MINVAL(zic_t, TIME_T_BITS_IN_FILE);
+static zic_t const max_time = MAXVAL(zic_t, TIME_T_BITS_IN_FILE);
+
+/* Estimated time of the Big Bang, in seconds since the POSIX epoch.
+   rounded downward to the negation of a power of two that is
+   comfortably outside the error bounds.
+
+   For the time of the Big Bang, see:
+
+   Ade PAR, Aghanim N, Armitage-Caplan C et al.  Planck 2013 results.
+   I. Overview of products and scientific results.
+   arXiv:1303.5062 2013-03-20 20:10:01 UTC
+   <https://arxiv.org/pdf/1303.5062v1> [PDF]
+
+   Page 36, Table 9, row Age/Gyr, column Planck+WP+highL+BAO 68% limits
+   gives the value 13.798 plus-or-minus 0.037 billion years.
+   Multiplying this by 1000000000 and then by 31557600 (the number of
+   seconds in an astronomical year) gives a value that is comfortably
+   less than 2**59, so BIG_BANG is - 2**59.
+
+   BIG_BANG is approximate, and may change in future versions.
+   Please do not rely on its exact value.  */
+
+#ifndef BIG_BANG
+#define BIG_BANG (- (1LL << 59))
+#endif
+
+/* If true, work around GNOME bug 730332
+   <https://bugzilla.gnome.org/show_bug.cgi?id=730332>
+   by refusing to output time stamps before BIG_BANG.
+   Such time stamps are physically suspect anyway.
+
+   The GNOME bug is scheduled to be fixed in GNOME 3.22, and if so
+   this workaround will no longer be needed when GNOME 3.21 and
+   earlier are obsolete, say in the year 2021.  */
+enum { WORK_AROUND_GNOME_BUG_730332 = true };
+
+static const zic_t early_time = (WORK_AROUND_GNOME_BUG_730332
+				 ? BIG_BANG
+				 : MINVAL(zic_t, TIME_T_BITS_IN_FILE));
+
+/* Return true if NAME is a directory.  */
+static bool
+itsdir(char const *name)
+{
+	struct stat st;
+	int res = stat(name, &st);
+#ifdef S_ISDIR
+	if (res == 0)
+		return S_ISDIR(st.st_mode) != 0;
+#endif
+	if (res == 0 || errno == EOVERFLOW) {
+		size_t n = strlen(name);
+		char *nameslashdot = emalloc(n + 3);
+		bool dir;
+		memcpy(nameslashdot, name, n);
+		strcpy(&nameslashdot[n], &"/."[! (n && name[n - 1] != '/')]);
+		dir = stat(nameslashdot, &st) == 0 || errno == EOVERFLOW;
+		free(nameslashdot);
+		return dir;
+	}
+	return false;
+}
+
+/* Return true if NAME is a symbolic link.  */
+static bool
+itssymlink(char const *name)
+{
+  char c;
+  return 0 <= readlink(name, &c, 1);
+}
+
+/*
+** Associate sets of rules with zones.
+*/
+
+/*
+** Sort by rule name.
+*/
+
+static int
+rcomp(const void *cp1, const void *cp2)
+{
+	return strcmp(((const struct rule *) cp1)->r_name,
+		((const struct rule *) cp2)->r_name);
+}
+
+static void
+associate(void)
+{
+	register struct zone *	zp;
+	register struct rule *	rp;
+	register ptrdiff_t i, j, base, out;
+
+	if (nrules != 0) {
+		qsort(rules, nrules, sizeof *rules, rcomp);
+		for (i = 0; i < nrules - 1; ++i) {
+			if (strcmp(rules[i].r_name,
+				rules[i + 1].r_name) != 0)
+					continue;
+			if (strcmp(rules[i].r_filename,
+				rules[i + 1].r_filename) == 0)
+					continue;
+			eat(rules[i].r_filename, rules[i].r_linenum);
+			warning(_("same rule name in multiple files"));
+			eat(rules[i + 1].r_filename, rules[i + 1].r_linenum);
+			warning(_("same rule name in multiple files"));
+			for (j = i + 2; j < nrules; ++j) {
+				if (strcmp(rules[i].r_name,
+					rules[j].r_name) != 0)
+						break;
+				if (strcmp(rules[i].r_filename,
+					rules[j].r_filename) == 0)
+						continue;
+				if (strcmp(rules[i + 1].r_filename,
+					rules[j].r_filename) == 0)
+						continue;
+				break;
+			}
+			i = j - 1;
+		}
+	}
+	for (i = 0; i < nzones; ++i) {
+		zp = &zones[i];
+		zp->z_rules = NULL;
+		zp->z_nrules = 0;
+	}
+	for (base = 0; base < nrules; base = out) {
+		rp = &rules[base];
+		for (out = base + 1; out < nrules; ++out)
+			if (strcmp(rp->r_name, rules[out].r_name) != 0)
+				break;
+		for (i = 0; i < nzones; ++i) {
+			zp = &zones[i];
+			if (strcmp(zp->z_rule, rp->r_name) != 0)
+				continue;
+			zp->z_rules = rp;
+			zp->z_nrules = out - base;
+		}
+	}
+	for (i = 0; i < nzones; ++i) {
+		zp = &zones[i];
+		if (zp->z_nrules == 0) {
+			/*
+			** Maybe we have a local standard time offset.
+			*/
+			eat(zp->z_filename, zp->z_linenum);
+			zp->z_stdoff = getstdoff(zp->z_rule, &zp->z_isdst);
+			/*
+			** Note, though, that if there's no rule,
+			** a '%s' in the format is a bad thing.
+			*/
+			if (zp->z_format_specifier == 's')
+				error("%s", _("%s in ruleless zone"));
+		}
+	}
+	if (errors)
+		exit(EXIT_FAILURE);
+}
+
+static void
+infile(const char *name)
+{
+	register FILE *			fp;
+	register char **		fields;
+	register char *			cp;
+	register const struct lookup *	lp;
+	register int			nfields;
+	register bool			wantcont;
+	register lineno			num;
+	char				buf[BUFSIZ];
+
+	if (strcmp(name, "-") == 0) {
+		name = _("standard input");
+		fp = stdin;
+	} else if ((fp = fopen(name, "r")) == NULL) {
+		const char *e = strerror(errno);
+
+		fprintf(stderr, _("%s: Can't open %s: %s\n"),
+			progname, name, e);
+		exit(EXIT_FAILURE);
+	}
+	wantcont = false;
+	for (num = 1; ; ++num) {
+		eat(name, num);
+		if (fgets(buf, sizeof buf, fp) != buf)
+			break;
+		cp = strchr(buf, '\n');
+		if (cp == NULL) {
+			error(_("line too long"));
+			exit(EXIT_FAILURE);
+		}
+		*cp = '\0';
+		fields = getfields(buf);
+		nfields = 0;
+		while (fields[nfields] != NULL) {
+			static char	nada;
+
+			if (strcmp(fields[nfields], "-") == 0)
+				fields[nfields] = &nada;
+			++nfields;
+		}
+		if (nfields == 0) {
+			/* nothing to do */
+		} else if (wantcont) {
+			wantcont = inzcont(fields, nfields);
+		} else {
+			struct lookup const *line_codes
+			  = name == leapsec ? leap_line_codes : zi_line_codes;
+			lp = byword(fields[0], line_codes);
+			if (lp == NULL)
+				error(_("input line of unknown type"));
+			else switch (lp->l_value) {
+				case LC_RULE:
+					inrule(fields, nfields);
+					wantcont = false;
+					break;
+				case LC_ZONE:
+					wantcont = inzone(fields, nfields);
+					break;
+				case LC_LINK:
+					inlink(fields, nfields);
+					wantcont = false;
+					break;
+				case LC_LEAP:
+					inleap(fields, nfields);
+					wantcont = false;
+					break;
+				default:	/* "cannot happen" */
+					fprintf(stderr,
+_("%s: panic: Invalid l_value %d\n"),
+						progname, lp->l_value);
+					exit(EXIT_FAILURE);
+			}
+		}
+		free(fields);
+	}
+	close_file(fp, NULL, filename);
+	if (wantcont)
+		error(_("expected continuation line not found"));
+}
+
+/*
+** Convert a string of one of the forms
+**	h	-h	hh:mm	-hh:mm	hh:mm:ss	-hh:mm:ss
+** into a number of seconds.
+** A null string maps to zero.
+** Call error with errstring and return zero on errors.
+*/
+
+static zic_t
+gethms(char const *string, char const *errstring, bool signable)
+{
+	zic_t	hh;
+	int sign, mm = 0, ss = 0;
+	char hhx, mmx, ssx, xr = '0', xs;
+	int tenths = 0;
+	bool ok = true;
+
+	if (string == NULL || *string == '\0')
+		return 0;
+	if (!signable)
+		sign = 1;
+	else if (*string == '-') {
+		sign = -1;
+		++string;
+	} else	sign = 1;
+	switch (sscanf(string,
+		       "%"SCNdZIC"%c%d%c%d%c%1d%*[0]%c%*[0123456789]%c",
+		       &hh, &hhx, &mm, &mmx, &ss, &ssx, &tenths, &xr, &xs)) {
+	  default: ok = false; break;
+	  case 8:
+	    ok = '0' <= xr && xr <= '9';
+	    /* fallthrough */
+	  case 7:
+	    ok &= ssx == '.';
+	    if (ok && noise)
+	      warning(_("fractional seconds rejected by"
+			" pre-2018 versions of zic"));
+	    /* fallthrough */
+	  case 5: ok &= mmx == ':'; /* fallthrough */
+	  case 3: ok &= hhx == ':'; /* fallthrough */
+	  case 1: break;
+	}
+	if (!ok) {
+			error("%s", errstring);
+			return 0;
+	}
+	if (hh < 0 ||
+		mm < 0 || mm >= MINSPERHOUR ||
+		ss < 0 || ss > SECSPERMIN) {
+			error("%s", errstring);
+			return 0;
+	}
+	if (ZIC_MAX / SECSPERHOUR < hh) {
+		error(_("time overflow"));
+		return 0;
+	}
+	ss += 5 + ((ss ^ 1) & (xr == '0')) <= tenths; /* Round to even.  */
+	if (noise && (hh > HOURSPERDAY ||
+		(hh == HOURSPERDAY && (mm != 0 || ss != 0))))
+warning(_("values over 24 hours not handled by pre-2007 versions of zic"));
+	return oadd(sign * hh * SECSPERHOUR,
+		    sign * (mm * SECSPERMIN + ss));
+}
+
+static zic_t
+getstdoff(char *field, bool *isdst)
+{
+  int dst = -1;
+  zic_t stdoff;
+  size_t fieldlen = strlen(field);
+  if (fieldlen != 0) {
+    char *ep = field + fieldlen - 1;
+    switch (*ep) {
+      case 'd': dst = 1; *ep = '\0'; break;
+      case 's': dst = 0; *ep = '\0'; break;
+    }
+  }
+  stdoff = gethms(field, _("invalid saved time"), true);
+  *isdst = dst < 0 ? stdoff != 0 : dst;
+  return stdoff;
+}
+
+static void
+inrule(char **fields, int nfields)
+{
+	static struct rule	r;
+
+	if (nfields != RULE_FIELDS) {
+		error(_("wrong number of fields on Rule line"));
+		return;
+	}
+	if (*fields[RF_NAME] == '\0') {
+		error(_("nameless rule"));
+		return;
+	}
+	r.r_filename = filename;
+	r.r_linenum = linenum;
+	r.r_stdoff = getstdoff(fields[RF_STDOFF], &r.r_isdst);
+	rulesub(&r, fields[RF_LOYEAR], fields[RF_HIYEAR], fields[RF_COMMAND],
+		fields[RF_MONTH], fields[RF_DAY], fields[RF_TOD]);
+	r.r_name = ecpyalloc(fields[RF_NAME]);
+	r.r_abbrvar = ecpyalloc(fields[RF_ABBRVAR]);
+	if (max_abbrvar_len < strlen(r.r_abbrvar))
+		max_abbrvar_len = strlen(r.r_abbrvar);
+	rules = growalloc(rules, sizeof *rules, nrules, &nrules_alloc);
+	rules[nrules++] = r;
+}
+
+static bool
+inzone(char **fields, int nfields)
+{
+	register ptrdiff_t i;
+
+	if (nfields < ZONE_MINFIELDS || nfields > ZONE_MAXFIELDS) {
+		error(_("wrong number of fields on Zone line"));
+		return false;
+	}
+	if (lcltime != NULL && strcmp(fields[ZF_NAME], tzdefault) == 0) {
+		error(
+_("\"Zone %s\" line and -l option are mutually exclusive"),
+			tzdefault);
+		return false;
+	}
+	if (strcmp(fields[ZF_NAME], TZDEFRULES) == 0 && psxrules != NULL) {
+		error(
+_("\"Zone %s\" line and -p option are mutually exclusive"),
+			TZDEFRULES);
+		return false;
+	}
+	for (i = 0; i < nzones; ++i)
+		if (zones[i].z_name != NULL &&
+			strcmp(zones[i].z_name, fields[ZF_NAME]) == 0) {
+				error(_("duplicate zone name %s"
+					" (file \"%s\", line %"PRIdMAX")"),
+					fields[ZF_NAME],
+					zones[i].z_filename,
+					zones[i].z_linenum);
+				return false;
+		}
+	return inzsub(fields, nfields, false);
+}
+
+static bool
+inzcont(char **fields, int nfields)
+{
+	if (nfields < ZONEC_MINFIELDS || nfields > ZONEC_MAXFIELDS) {
+		error(_("wrong number of fields on Zone continuation line"));
+		return false;
+	}
+	return inzsub(fields, nfields, true);
+}
+
+static bool
+inzsub(char **fields, int nfields, bool iscont)
+{
+	register char *		cp;
+	char *			cp1;
+	static struct zone	z;
+	register int		i_gmtoff, i_rule, i_format;
+	register int		i_untilyear, i_untilmonth;
+	register int		i_untilday, i_untiltime;
+	register bool		hasuntil;
+
+	if (iscont) {
+		i_gmtoff = ZFC_GMTOFF;
+		i_rule = ZFC_RULE;
+		i_format = ZFC_FORMAT;
+		i_untilyear = ZFC_TILYEAR;
+		i_untilmonth = ZFC_TILMONTH;
+		i_untilday = ZFC_TILDAY;
+		i_untiltime = ZFC_TILTIME;
+		z.z_name = NULL;
+	} else if (!namecheck(fields[ZF_NAME]))
+		return false;
+	else {
+		i_gmtoff = ZF_GMTOFF;
+		i_rule = ZF_RULE;
+		i_format = ZF_FORMAT;
+		i_untilyear = ZF_TILYEAR;
+		i_untilmonth = ZF_TILMONTH;
+		i_untilday = ZF_TILDAY;
+		i_untiltime = ZF_TILTIME;
+		z.z_name = ecpyalloc(fields[ZF_NAME]);
+	}
+	z.z_filename = filename;
+	z.z_linenum = linenum;
+	z.z_gmtoff = gethms(fields[i_gmtoff], _("invalid UT offset"), true);
+	if ((cp = strchr(fields[i_format], '%')) != 0) {
+		if ((*++cp != 's' && *cp != 'z') || strchr(cp, '%')
+		    || strchr(fields[i_format], '/')) {
+			error(_("invalid abbreviation format"));
+			return false;
+		}
+	}
+	z.z_rule = ecpyalloc(fields[i_rule]);
+	z.z_format = cp1 = ecpyalloc(fields[i_format]);
+	z.z_format_specifier = cp ? *cp : '\0';
+	if (z.z_format_specifier == 'z') {
+	  if (noise)
+	    warning(_("format '%s' not handled by pre-2015 versions of zic"),
+		    z.z_format);
+	  cp1[cp - fields[i_format]] = 's';
+	}
+	if (max_format_len < strlen(z.z_format))
+		max_format_len = strlen(z.z_format);
+	hasuntil = nfields > i_untilyear;
+	if (hasuntil) {
+		z.z_untilrule.r_filename = filename;
+		z.z_untilrule.r_linenum = linenum;
+		rulesub(&z.z_untilrule,
+			fields[i_untilyear],
+			"only",
+			"",
+			(nfields > i_untilmonth) ?
+			fields[i_untilmonth] : "Jan",
+			(nfields > i_untilday) ? fields[i_untilday] : "1",
+			(nfields > i_untiltime) ? fields[i_untiltime] : "0");
+		z.z_untiltime = rpytime(&z.z_untilrule,
+			z.z_untilrule.r_loyear);
+		if (iscont && nzones > 0 &&
+			z.z_untiltime > min_time &&
+			z.z_untiltime < max_time &&
+			zones[nzones - 1].z_untiltime > min_time &&
+			zones[nzones - 1].z_untiltime < max_time &&
+			zones[nzones - 1].z_untiltime >= z.z_untiltime) {
+				error(_(
+"Zone continuation line end time is not after end time of previous line"
+					));
+				return false;
+		}
+	}
+	zones = growalloc(zones, sizeof *zones, nzones, &nzones_alloc);
+	zones[nzones++] = z;
+	/*
+	** If there was an UNTIL field on this line,
+	** there's more information about the zone on the next line.
+	*/
+	return hasuntil;
+}
+
+static void
+inleap(char **fields, int nfields)
+{
+	register const char *		cp;
+	register const struct lookup *	lp;
+	register zic_t			i, j;
+	zic_t				year;
+	int				month, day;
+	zic_t				dayoff, tod;
+	zic_t				t;
+	char xs;
+
+	if (nfields != LEAP_FIELDS) {
+		error(_("wrong number of fields on Leap line"));
+		return;
+	}
+	dayoff = 0;
+	cp = fields[LP_YEAR];
+	if (sscanf(cp, "%"SCNdZIC"%c", &year, &xs) != 1) {
+		/*
+		** Leapin' Lizards!
+		*/
+		error(_("invalid leaping year"));
+		return;
+	}
+	if (!leapseen || leapmaxyear < year)
+		leapmaxyear = year;
+	if (!leapseen || leapminyear > year)
+		leapminyear = year;
+	leapseen = true;
+	j = EPOCH_YEAR;
+	while (j != year) {
+		if (year > j) {
+			i = len_years[isleap(j)];
+			++j;
+		} else {
+			--j;
+			i = -len_years[isleap(j)];
+		}
+		dayoff = oadd(dayoff, i);
+	}
+	if ((lp = byword(fields[LP_MONTH], mon_names)) == NULL) {
+		error(_("invalid month name"));
+		return;
+	}
+	month = lp->l_value;
+	j = TM_JANUARY;
+	while (j != month) {
+		i = len_months[isleap(year)][j];
+		dayoff = oadd(dayoff, i);
+		++j;
+	}
+	cp = fields[LP_DAY];
+	if (sscanf(cp, "%d%c", &day, &xs) != 1 ||
+		day <= 0 || day > len_months[isleap(year)][month]) {
+			error(_("invalid day of month"));
+			return;
+	}
+	dayoff = oadd(dayoff, day - 1);
+	if (dayoff < min_time / SECSPERDAY) {
+		error(_("time too small"));
+		return;
+	}
+	if (dayoff > max_time / SECSPERDAY) {
+		error(_("time too large"));
+		return;
+	}
+	t = dayoff * SECSPERDAY;
+	tod = gethms(fields[LP_TIME], _("invalid time of day"), false);
+	cp = fields[LP_CORR];
+	{
+		register bool	positive;
+		int		count;
+
+		if (strcmp(cp, "") == 0) { /* infile() turns "-" into "" */
+			positive = false;
+			count = 1;
+		} else if (strcmp(cp, "+") == 0) {
+			positive = true;
+			count = 1;
+		} else {
+			error(_("illegal CORRECTION field on Leap line"));
+			return;
+		}
+		if ((lp = byword(fields[LP_ROLL], leap_types)) == NULL) {
+			error(_(
+				"illegal Rolling/Stationary field on Leap line"
+				));
+			return;
+		}
+		t = tadd(t, tod);
+		if (t < 0) {
+			error(_("leap second precedes Epoch"));
+			return;
+		}
+		leapadd(t, positive, lp->l_value, count);
+	}
+}
+
+static void
+inlink(char **fields, int nfields)
+{
+	struct link	l;
+
+	if (nfields != LINK_FIELDS) {
+		error(_("wrong number of fields on Link line"));
+		return;
+	}
+	if (*fields[LF_FROM] == '\0') {
+		error(_("blank FROM field on Link line"));
+		return;
+	}
+	if (! namecheck(fields[LF_TO]))
+	  return;
+	l.l_filename = filename;
+	l.l_linenum = linenum;
+	l.l_from = ecpyalloc(fields[LF_FROM]);
+	l.l_to = ecpyalloc(fields[LF_TO]);
+	links = growalloc(links, sizeof *links, nlinks, &nlinks_alloc);
+	links[nlinks++] = l;
+}
+
+static void
+rulesub(struct rule *rp, const char *loyearp, const char *hiyearp,
+	const char *typep, const char *monthp, const char *dayp,
+	const char *timep)
+{
+	register const struct lookup *	lp;
+	register const char *		cp;
+	register char *			dp;
+	register char *			ep;
+	char xs;
+
+	if ((lp = byword(monthp, mon_names)) == NULL) {
+		error(_("invalid month name"));
+		return;
+	}
+	rp->r_month = lp->l_value;
+	rp->r_todisstd = false;
+	rp->r_todisgmt = false;
+	dp = ecpyalloc(timep);
+	if (*dp != '\0') {
+		ep = dp + strlen(dp) - 1;
+		switch (lowerit(*ep)) {
+			case 's':	/* Standard */
+				rp->r_todisstd = true;
+				rp->r_todisgmt = false;
+				*ep = '\0';
+				break;
+			case 'w':	/* Wall */
+				rp->r_todisstd = false;
+				rp->r_todisgmt = false;
+				*ep = '\0';
+				break;
+			case 'g':	/* Greenwich */
+			case 'u':	/* Universal */
+			case 'z':	/* Zulu */
+				rp->r_todisstd = true;
+				rp->r_todisgmt = true;
+				*ep = '\0';
+				break;
+		}
+	}
+	rp->r_tod = gethms(dp, _("invalid time of day"), false);
+	free(dp);
+	/*
+	** Year work.
+	*/
+	cp = loyearp;
+	lp = byword(cp, begin_years);
+	rp->r_lowasnum = lp == NULL;
+	if (!rp->r_lowasnum) switch (lp->l_value) {
+		case YR_MINIMUM:
+			rp->r_loyear = ZIC_MIN;
+			break;
+		case YR_MAXIMUM:
+			rp->r_loyear = ZIC_MAX;
+			break;
+		default:	/* "cannot happen" */
+			fprintf(stderr,
+				_("%s: panic: Invalid l_value %d\n"),
+				progname, lp->l_value);
+			exit(EXIT_FAILURE);
+	} else if (sscanf(cp, "%"SCNdZIC"%c", &rp->r_loyear, &xs) != 1) {
+		error(_("invalid starting year"));
+		return;
+	}
+	cp = hiyearp;
+	lp = byword(cp, end_years);
+	rp->r_hiwasnum = lp == NULL;
+	if (!rp->r_hiwasnum) switch (lp->l_value) {
+		case YR_MINIMUM:
+			rp->r_hiyear = ZIC_MIN;
+			break;
+		case YR_MAXIMUM:
+			rp->r_hiyear = ZIC_MAX;
+			break;
+		case YR_ONLY:
+			rp->r_hiyear = rp->r_loyear;
+			break;
+		default:	/* "cannot happen" */
+			fprintf(stderr,
+				_("%s: panic: Invalid l_value %d\n"),
+				progname, lp->l_value);
+			exit(EXIT_FAILURE);
+	} else if (sscanf(cp, "%"SCNdZIC"%c", &rp->r_hiyear, &xs) != 1) {
+		error(_("invalid ending year"));
+		return;
+	}
+	if (rp->r_loyear > rp->r_hiyear) {
+		error(_("starting year greater than ending year"));
+		return;
+	}
+	if (*typep == '\0')
+		rp->r_yrtype = NULL;
+	else {
+		if (rp->r_loyear == rp->r_hiyear) {
+			error(_("typed single year"));
+			return;
+		}
+		warning(_("year type \"%s\" is obsolete; use \"-\" instead"),
+			typep);
+		rp->r_yrtype = ecpyalloc(typep);
+	}
+	/*
+	** Day work.
+	** Accept things such as:
+	**	1
+	**	lastSunday
+	**	last-Sunday (undocumented; warn about this)
+	**	Sun<=20
+	**	Sun>=7
+	*/
+	dp = ecpyalloc(dayp);
+	if ((lp = byword(dp, lasts)) != NULL) {
+		rp->r_dycode = DC_DOWLEQ;
+		rp->r_wday = lp->l_value;
+		rp->r_dayofmonth = len_months[1][rp->r_month];
+	} else {
+		if ((ep = strchr(dp, '<')) != 0)
+			rp->r_dycode = DC_DOWLEQ;
+		else if ((ep = strchr(dp, '>')) != 0)
+			rp->r_dycode = DC_DOWGEQ;
+		else {
+			ep = dp;
+			rp->r_dycode = DC_DOM;
+		}
+		if (rp->r_dycode != DC_DOM) {
+			*ep++ = 0;
+			if (*ep++ != '=') {
+				error(_("invalid day of month"));
+				free(dp);
+				return;
+			}
+			if ((lp = byword(dp, wday_names)) == NULL) {
+				error(_("invalid weekday name"));
+				free(dp);
+				return;
+			}
+			rp->r_wday = lp->l_value;
+		}
+		if (sscanf(ep, "%d%c", &rp->r_dayofmonth, &xs) != 1 ||
+			rp->r_dayofmonth <= 0 ||
+			(rp->r_dayofmonth > len_months[1][rp->r_month])) {
+				error(_("invalid day of month"));
+				free(dp);
+				return;
+		}
+	}
+	free(dp);
+}
+
+static void
+convert(const int_fast32_t val, char *const buf)
+{
+	register int	i;
+	register int	shift;
+	unsigned char *const b = (unsigned char *) buf;
+
+	for (i = 0, shift = 24; i < 4; ++i, shift -= 8)
+		b[i] = val >> shift;
+}
+
+static void
+convert64(const zic_t val, char *const buf)
+{
+	register int	i;
+	register int	shift;
+	unsigned char *const b = (unsigned char *) buf;
+
+	for (i = 0, shift = 56; i < 8; ++i, shift -= 8)
+		b[i] = val >> shift;
+}
+
+static void
+puttzcode(const int_fast32_t val, FILE *const fp)
+{
+	char	buf[4];
+
+	convert(val, buf);
+	fwrite(buf, sizeof buf, 1, fp);
+}
+
+static void
+puttzcode64(const zic_t val, FILE *const fp)
+{
+	char	buf[8];
+
+	convert64(val, buf);
+	fwrite(buf, sizeof buf, 1, fp);
+}
+
+static int
+atcomp(const void *avp, const void *bvp)
+{
+	const zic_t	a = ((const struct attype *) avp)->at;
+	const zic_t	b = ((const struct attype *) bvp)->at;
+
+	return (a < b) ? -1 : (a > b);
+}
+
+static bool
+is32(const zic_t x)
+{
+	return INT32_MIN <= x && x <= INT32_MAX;
+}
+
+static void
+writezone(const char *const name, const char *const string, char version)
+{
+	register FILE *			fp;
+	register ptrdiff_t		i, j;
+	register int			leapcnt32, leapi32;
+	register ptrdiff_t		timecnt32, timei32;
+	register int			pass;
+	static const struct tzhead	tzh0;
+	static struct tzhead		tzh;
+	bool dir_checked = false;
+	zic_t one = 1;
+	zic_t y2038_boundary = one << 31;
+	ptrdiff_t nats = timecnt + WORK_AROUND_QTBUG_53071;
+	zic_t *ats = emalloc(size_product(nats, sizeof *ats + 1));
+	void *typesptr = ats + nats;
+	unsigned char *types = typesptr;
+
+	/*
+	** Sort.
+	*/
+	if (timecnt > 1)
+		qsort(attypes, timecnt, sizeof *attypes, atcomp);
+	/*
+	** Optimize.
+	*/
+	{
+		ptrdiff_t fromi, toi;
+
+		toi = 0;
+		fromi = 0;
+		while (fromi < timecnt && attypes[fromi].at < early_time)
+			++fromi;
+		for ( ; fromi < timecnt; ++fromi) {
+			if (toi > 1 && ((attypes[fromi].at +
+				gmtoffs[attypes[toi - 1].type]) <=
+				(attypes[toi - 1].at +
+				gmtoffs[attypes[toi - 2].type]))) {
+					attypes[toi - 1].type =
+						attypes[fromi].type;
+					continue;
+			}
+			if (toi == 0
+			    || attypes[fromi].dontmerge
+			    || attypes[toi - 1].type != attypes[fromi].type)
+					attypes[toi++] = attypes[fromi];
+		}
+		timecnt = toi;
+	}
+
+	if (noise && timecnt > 1200) {
+	  if (timecnt > TZ_MAX_TIMES)
+		warning(_("reference clients mishandle"
+			  " more than %d transition times"),
+			TZ_MAX_TIMES);
+	  else
+		warning(_("pre-2014 clients may mishandle"
+			  " more than 1200 transition times"));
+	}
+	/*
+	** Transfer.
+	*/
+	for (i = 0; i < timecnt; ++i) {
+		ats[i] = attypes[i].at;
+		types[i] = attypes[i].type;
+	}
+
+	/* Work around QTBUG-53071 for time stamps less than y2038_boundary - 1,
+	   by inserting a no-op transition at time y2038_boundary - 1.
+	   This works only for timestamps before the boundary, which
+	   should be good enough in practice as QTBUG-53071 should be
+	   long-dead by 2038.  */
+	if (WORK_AROUND_QTBUG_53071 && timecnt != 0
+	    && ats[timecnt - 1] < y2038_boundary - 1 && strchr(string, '<')) {
+	  ats[timecnt] = y2038_boundary - 1;
+	  types[timecnt] = types[timecnt - 1];
+	  timecnt++;
+	}
+
+	/*
+	** Correct for leap seconds.
+	*/
+	for (i = 0; i < timecnt; ++i) {
+		j = leapcnt;
+		while (--j >= 0)
+			if (ats[i] > trans[j] - corr[j]) {
+				ats[i] = tadd(ats[i], corr[j]);
+				break;
+			}
+	}
+	/*
+	** Figure out 32-bit-limited starts and counts.
+	*/
+	timecnt32 = timecnt;
+	timei32 = 0;
+	leapcnt32 = leapcnt;
+	leapi32 = 0;
+	while (timecnt32 > 0 && !is32(ats[timecnt32 - 1]))
+		--timecnt32;
+	while (timecnt32 > 0 && !is32(ats[timei32])) {
+		--timecnt32;
+		++timei32;
+	}
+	/*
+	** Output an INT32_MIN "transition" if appropriate; see below.
+	*/
+	if (timei32 > 0 && ats[timei32] > INT32_MIN) {
+		--timei32;
+		++timecnt32;
+	}
+	while (leapcnt32 > 0 && !is32(trans[leapcnt32 - 1]))
+		--leapcnt32;
+	while (leapcnt32 > 0 && !is32(trans[leapi32])) {
+		--leapcnt32;
+		++leapi32;
+	}
+	/*
+	** Remove old file, if any, to snap links.
+	*/
+	if (remove(name) == 0)
+		dir_checked = true;
+	else if (errno != ENOENT) {
+		const char *e = strerror(errno);
+
+		fprintf(stderr, _("%s: Can't remove %s/%s: %s\n"),
+			progname, directory, name, e);
+		exit(EXIT_FAILURE);
+	}
+	fp = fopen(name, "wb");
+	if (!fp) {
+	  int fopen_errno = errno;
+	  if (fopen_errno == ENOENT && !dir_checked) {
+	    mkdirs(name, true);
+	    fp = fopen(name, "wb");
+	    fopen_errno = errno;
+	  }
+	  if (!fp) {
+	    fprintf(stderr, _("%s: Can't create %s/%s: %s\n"),
+		    progname, directory, name, strerror(fopen_errno));
+	    exit(EXIT_FAILURE);
+	  }
+	}
+	for (pass = 1; pass <= 2; ++pass) {
+		register ptrdiff_t thistimei, thistimecnt, thistimelim;
+		register int	thisleapi, thisleapcnt, thisleaplim;
+		int		writetype[TZ_MAX_TYPES];
+		int		typemap[TZ_MAX_TYPES];
+		register int	thistypecnt;
+		char		thischars[TZ_MAX_CHARS];
+		int		thischarcnt;
+		bool		toomanytimes;
+		int		indmap[TZ_MAX_CHARS];
+
+		if (pass == 1) {
+			thistimei = timei32;
+			thistimecnt = timecnt32;
+			toomanytimes = thistimecnt >> 31 >> 1 != 0;
+			thisleapi = leapi32;
+			thisleapcnt = leapcnt32;
+		} else {
+			thistimei = 0;
+			thistimecnt = timecnt;
+			toomanytimes = thistimecnt >> 31 >> 31 >> 2 != 0;
+			thisleapi = 0;
+			thisleapcnt = leapcnt;
+		}
+		if (toomanytimes)
+		  error(_("too many transition times"));
+		thistimelim = thistimei + thistimecnt;
+		thisleaplim = thisleapi + thisleapcnt;
+		for (i = 0; i < typecnt; ++i)
+			writetype[i] = thistimecnt == timecnt;
+		if (thistimecnt == 0) {
+			/*
+			** No transition times fall in the current
+			** (32- or 64-bit) window.
+			*/
+			if (typecnt != 0)
+				writetype[typecnt - 1] = true;
+		} else {
+			for (i = thistimei - 1; i < thistimelim; ++i)
+				if (i >= 0)
+					writetype[types[i]] = true;
+			/*
+			** For America/Godthab and Antarctica/Palmer
+			*/
+			if (thistimei == 0)
+				writetype[0] = true;
+		}
+#ifndef LEAVE_SOME_PRE_2011_SYSTEMS_IN_THE_LURCH
+		/*
+		** For some pre-2011 systems: if the last-to-be-written
+		** standard (or daylight) type has an offset different from the
+		** most recently used offset,
+		** append an (unused) copy of the most recently used type
+		** (to help get global "altzone" and "timezone" variables
+		** set correctly).
+		*/
+		{
+			register int	mrudst, mrustd, hidst, histd, type;
+
+			hidst = histd = mrudst = mrustd = -1;
+			for (i = thistimei; i < thistimelim; ++i)
+				if (isdsts[types[i]])
+					mrudst = types[i];
+				else	mrustd = types[i];
+			for (i = 0; i < typecnt; ++i)
+				if (writetype[i]) {
+					if (isdsts[i])
+						hidst = i;
+					else	histd = i;
+				}
+			if (hidst >= 0 && mrudst >= 0 && hidst != mrudst &&
+				gmtoffs[hidst] != gmtoffs[mrudst]) {
+					isdsts[mrudst] = -1;
+					type = addtype(gmtoffs[mrudst],
+						&chars[abbrinds[mrudst]],
+						true,
+						ttisstds[mrudst],
+						ttisgmts[mrudst]);
+					isdsts[mrudst] = 1;
+					writetype[type] = true;
+			}
+			if (histd >= 0 && mrustd >= 0 && histd != mrustd &&
+				gmtoffs[histd] != gmtoffs[mrustd]) {
+					isdsts[mrustd] = -1;
+					type = addtype(gmtoffs[mrustd],
+						&chars[abbrinds[mrustd]],
+						false,
+						ttisstds[mrustd],
+						ttisgmts[mrustd]);
+					isdsts[mrustd] = 0;
+					writetype[type] = true;
+			}
+		}
+#endif /* !defined LEAVE_SOME_PRE_2011_SYSTEMS_IN_THE_LURCH */
+		thistypecnt = 0;
+		for (i = 0; i < typecnt; ++i)
+			typemap[i] = writetype[i] ?  thistypecnt++ : -1;
+		for (i = 0; i < sizeof indmap / sizeof indmap[0]; ++i)
+			indmap[i] = -1;
+		thischarcnt = 0;
+		for (i = 0; i < typecnt; ++i) {
+			register char *	thisabbr;
+
+			if (!writetype[i])
+				continue;
+			if (indmap[abbrinds[i]] >= 0)
+				continue;
+			thisabbr = &chars[abbrinds[i]];
+			for (j = 0; j < thischarcnt; ++j)
+				if (strcmp(&thischars[j], thisabbr) == 0)
+					break;
+			if (j == thischarcnt) {
+				strcpy(&thischars[thischarcnt], thisabbr);
+				thischarcnt += strlen(thisabbr) + 1;
+			}
+			indmap[abbrinds[i]] = j;
+		}
+#define DO(field)	fwrite(tzh.field, sizeof tzh.field, 1, fp)
+		tzh = tzh0;
+		memcpy(tzh.tzh_magic, TZ_MAGIC, sizeof tzh.tzh_magic);
+		tzh.tzh_version[0] = version;
+		convert(thistypecnt, tzh.tzh_ttisgmtcnt);
+		convert(thistypecnt, tzh.tzh_ttisstdcnt);
+		convert(thisleapcnt, tzh.tzh_leapcnt);
+		convert(thistimecnt, tzh.tzh_timecnt);
+		convert(thistypecnt, tzh.tzh_typecnt);
+		convert(thischarcnt, tzh.tzh_charcnt);
+		DO(tzh_magic);
+		DO(tzh_version);
+		DO(tzh_reserved);
+		DO(tzh_ttisgmtcnt);
+		DO(tzh_ttisstdcnt);
+		DO(tzh_leapcnt);
+		DO(tzh_timecnt);
+		DO(tzh_typecnt);
+		DO(tzh_charcnt);
+#undef DO
+		for (i = thistimei; i < thistimelim; ++i)
+			if (pass == 1)
+				/*
+				** Output an INT32_MIN "transition"
+				** if appropriate; see above.
+				*/
+				puttzcode(((ats[i] < INT32_MIN) ?
+					INT32_MIN : ats[i]), fp);
+			else	puttzcode64(ats[i], fp);
+		for (i = thistimei; i < thistimelim; ++i) {
+			unsigned char	uc;
+
+			uc = typemap[types[i]];
+			fwrite(&uc, sizeof uc, 1, fp);
+		}
+		for (i = 0; i < typecnt; ++i)
+			if (writetype[i]) {
+				puttzcode(gmtoffs[i], fp);
+				putc(isdsts[i], fp);
+				putc((unsigned char) indmap[abbrinds[i]], fp);
+			}
+		if (thischarcnt != 0)
+			fwrite(thischars, sizeof thischars[0],
+				      thischarcnt, fp);
+		for (i = thisleapi; i < thisleaplim; ++i) {
+			register zic_t	todo;
+
+			if (roll[i]) {
+				if (timecnt == 0 || trans[i] < ats[0]) {
+					j = 0;
+					while (isdsts[j])
+						if (++j >= typecnt) {
+							j = 0;
+							break;
+						}
+				} else {
+					j = 1;
+					while (j < timecnt &&
+						trans[i] >= ats[j])
+							++j;
+					j = types[j - 1];
+				}
+				todo = tadd(trans[i], -gmtoffs[j]);
+			} else	todo = trans[i];
+			if (pass == 1)
+				puttzcode(todo, fp);
+			else	puttzcode64(todo, fp);
+			puttzcode(corr[i], fp);
+		}
+		for (i = 0; i < typecnt; ++i)
+			if (writetype[i])
+				putc(ttisstds[i], fp);
+		for (i = 0; i < typecnt; ++i)
+			if (writetype[i])
+				putc(ttisgmts[i], fp);
+	}
+	fprintf(fp, "\n%s\n", string);
+	close_file(fp, directory, name);
+	free(ats);
+}
+
+static char const *
+abbroffset(char *buf, zic_t offset)
+{
+  char sign = '+';
+  int seconds, minutes;
+
+  if (offset < 0) {
+    offset = -offset;
+    sign = '-';
+  }
+
+  seconds = offset % SECSPERMIN;
+  offset /= SECSPERMIN;
+  minutes = offset % MINSPERHOUR;
+  offset /= MINSPERHOUR;
+  if (100 <= offset) {
+    error(_("%%z UT offset magnitude exceeds 99:59:59"));
+    return "%z";
+  } else {
+    char *p = buf;
+    *p++ = sign;
+    *p++ = '0' + offset / 10;
+    *p++ = '0' + offset % 10;
+    if (minutes | seconds) {
+      *p++ = '0' + minutes / 10;
+      *p++ = '0' + minutes % 10;
+      if (seconds) {
+	*p++ = '0' + seconds / 10;
+	*p++ = '0' + seconds % 10;
+      }
+    }
+    *p = '\0';
+    return buf;
+  }
+}
+
+static size_t
+doabbr(char *abbr, struct zone const *zp, char const *letters,
+       bool isdst, zic_t stdoff, bool doquotes)
+{
+	register char *	cp;
+	register char *	slashp;
+	register size_t	len;
+	char const *format = zp->z_format;
+
+	slashp = strchr(format, '/');
+	if (slashp == NULL) {
+	  char letterbuf[PERCENT_Z_LEN_BOUND + 1];
+	  if (zp->z_format_specifier == 'z')
+	    letters = abbroffset(letterbuf, zp->z_gmtoff + stdoff);
+	  else if (!letters)
+	    letters = "%s";
+	  sprintf(abbr, format, letters);
+	} else if (isdst) {
+		strcpy(abbr, slashp + 1);
+	} else {
+		memcpy(abbr, format, slashp - format);
+		abbr[slashp - format] = '\0';
+	}
+	len = strlen(abbr);
+	if (!doquotes)
+		return len;
+	for (cp = abbr; is_alpha(*cp); cp++)
+		continue;
+	if (len > 0 && *cp == '\0')
+		return len;
+	abbr[len + 2] = '\0';
+	abbr[len + 1] = '>';
+	memmove(abbr + 1, abbr, len);
+	abbr[0] = '<';
+	return len + 2;
+}
+
+static void
+updateminmax(const zic_t x)
+{
+	if (min_year > x)
+		min_year = x;
+	if (max_year < x)
+		max_year = x;
+}
+
+static int
+stringoffset(char *result, zic_t offset)
+{
+	register int	hours;
+	register int	minutes;
+	register int	seconds;
+	bool negative = offset < 0;
+	int len = negative;
+
+	if (negative) {
+		offset = -offset;
+		result[0] = '-';
+	}
+	seconds = offset % SECSPERMIN;
+	offset /= SECSPERMIN;
+	minutes = offset % MINSPERHOUR;
+	offset /= MINSPERHOUR;
+	hours = offset;
+	if (hours >= HOURSPERDAY * DAYSPERWEEK) {
+		result[0] = '\0';
+		return 0;
+	}
+	len += sprintf(result + len, "%d", hours);
+	if (minutes != 0 || seconds != 0) {
+		len += sprintf(result + len, ":%02d", minutes);
+		if (seconds != 0)
+			len += sprintf(result + len, ":%02d", seconds);
+	}
+	return len;
+}
+
+static int
+stringrule(char *result, const struct rule *const rp, const zic_t dstoff,
+	   const zic_t gmtoff)
+{
+	register zic_t	tod = rp->r_tod;
+	register int	compat = 0;
+
+	if (rp->r_dycode == DC_DOM) {
+		register int	month, total;
+
+		if (rp->r_dayofmonth == 29 && rp->r_month == TM_FEBRUARY)
+			return -1;
+		total = 0;
+		for (month = 0; month < rp->r_month; ++month)
+			total += len_months[0][month];
+		/* Omit the "J" in Jan and Feb, as that's shorter.  */
+		if (rp->r_month <= 1)
+		  result += sprintf(result, "%d", total + rp->r_dayofmonth - 1);
+		else
+		  result += sprintf(result, "J%d", total + rp->r_dayofmonth);
+	} else {
+		register int	week;
+		register int	wday = rp->r_wday;
+		register int	wdayoff;
+
+		if (rp->r_dycode == DC_DOWGEQ) {
+			wdayoff = (rp->r_dayofmonth - 1) % DAYSPERWEEK;
+			if (wdayoff)
+				compat = 2013;
+			wday -= wdayoff;
+			tod += wdayoff * SECSPERDAY;
+			week = 1 + (rp->r_dayofmonth - 1) / DAYSPERWEEK;
+		} else if (rp->r_dycode == DC_DOWLEQ) {
+			if (rp->r_dayofmonth == len_months[1][rp->r_month])
+				week = 5;
+			else {
+				wdayoff = rp->r_dayofmonth % DAYSPERWEEK;
+				if (wdayoff)
+					compat = 2013;
+				wday -= wdayoff;
+				tod += wdayoff * SECSPERDAY;
+				week = rp->r_dayofmonth / DAYSPERWEEK;
+			}
+		} else	return -1;	/* "cannot happen" */
+		if (wday < 0)
+			wday += DAYSPERWEEK;
+		result += sprintf(result, "M%d.%d.%d",
+				  rp->r_month + 1, week, wday);
+	}
+	if (rp->r_todisgmt)
+		tod += gmtoff;
+	if (rp->r_todisstd && !rp->r_isdst)
+		tod += dstoff;
+	if (tod != 2 * SECSPERMIN * MINSPERHOUR) {
+		*result++ = '/';
+		if (! stringoffset(result, tod))
+			return -1;
+		if (tod < 0) {
+			if (compat < 2013)
+				compat = 2013;
+		} else if (SECSPERDAY <= tod) {
+			if (compat < 1994)
+				compat = 1994;
+		}
+	}
+	return compat;
+}
+
+static int
+rule_cmp(struct rule const *a, struct rule const *b)
+{
+	if (!a)
+		return -!!b;
+	if (!b)
+		return 1;
+	if (a->r_hiyear != b->r_hiyear)
+		return a->r_hiyear < b->r_hiyear ? -1 : 1;
+	if (a->r_month - b->r_month != 0)
+		return a->r_month - b->r_month;
+	return a->r_dayofmonth - b->r_dayofmonth;
+}
+
+enum { YEAR_BY_YEAR_ZONE = 1 };
+
+static int
+stringzone(char *result, struct zone const *zpfirst, ptrdiff_t zonecount)
+{
+	register const struct zone *	zp;
+	register struct rule *		rp;
+	register struct rule *		stdrp;
+	register struct rule *		dstrp;
+	register ptrdiff_t		i;
+	register const char *		abbrvar;
+	register int			compat = 0;
+	register int			c;
+	size_t				len;
+	int				offsetlen;
+	struct rule			stdr, dstr;
+
+	result[0] = '\0';
+	zp = zpfirst + zonecount - 1;
+	stdrp = dstrp = NULL;
+	for (i = 0; i < zp->z_nrules; ++i) {
+		rp = &zp->z_rules[i];
+		if (rp->r_hiwasnum || rp->r_hiyear != ZIC_MAX)
+			continue;
+		if (rp->r_yrtype != NULL)
+			continue;
+		if (!rp->r_isdst) {
+			if (stdrp == NULL)
+				stdrp = rp;
+			else	return -1;
+		} else {
+			if (dstrp == NULL)
+				dstrp = rp;
+			else	return -1;
+		}
+	}
+	if (stdrp == NULL && dstrp == NULL) {
+		/*
+		** There are no rules running through "max".
+		** Find the latest std rule in stdabbrrp
+		** and latest rule of any type in stdrp.
+		*/
+		register struct rule *stdabbrrp = NULL;
+		for (i = 0; i < zp->z_nrules; ++i) {
+			rp = &zp->z_rules[i];
+			if (!rp->r_isdst && rule_cmp(stdabbrrp, rp) < 0)
+				stdabbrrp = rp;
+			if (rule_cmp(stdrp, rp) < 0)
+				stdrp = rp;
+		}
+		/*
+		** Horrid special case: if year is 2037,
+		** presume this is a zone handled on a year-by-year basis;
+		** do not try to apply a rule to the zone.
+		*/
+		if (stdrp != NULL && stdrp->r_hiyear == 2037)
+			return YEAR_BY_YEAR_ZONE;
+
+		if (stdrp != NULL && stdrp->r_isdst) {
+			/* Perpetual DST.  */
+			dstr.r_month = TM_JANUARY;
+			dstr.r_dycode = DC_DOM;
+			dstr.r_dayofmonth = 1;
+			dstr.r_tod = 0;
+			dstr.r_todisstd = dstr.r_todisgmt = false;
+			dstr.r_isdst = stdrp->r_isdst;
+			dstr.r_stdoff = stdrp->r_stdoff;
+			dstr.r_abbrvar = stdrp->r_abbrvar;
+			stdr.r_month = TM_DECEMBER;
+			stdr.r_dycode = DC_DOM;
+			stdr.r_dayofmonth = 31;
+			stdr.r_tod = SECSPERDAY + stdrp->r_stdoff;
+			stdr.r_todisstd = stdr.r_todisgmt = false;
+			stdr.r_isdst = false;
+			stdr.r_stdoff = 0;
+			stdr.r_abbrvar
+			  = (stdabbrrp ? stdabbrrp->r_abbrvar : "");
+			dstrp = &dstr;
+			stdrp = &stdr;
+		}
+	}
+	if (stdrp == NULL && (zp->z_nrules != 0 || zp->z_isdst))
+		return -1;
+	abbrvar = (stdrp == NULL) ? "" : stdrp->r_abbrvar;
+	len = doabbr(result, zp, abbrvar, false, 0, true);
+	offsetlen = stringoffset(result + len, -zp->z_gmtoff);
+	if (! offsetlen) {
+		result[0] = '\0';
+		return -1;
+	}
+	len += offsetlen;
+	if (dstrp == NULL)
+		return compat;
+	len += doabbr(result + len, zp, dstrp->r_abbrvar,
+		      dstrp->r_isdst, dstrp->r_stdoff, true);
+	if (dstrp->r_stdoff != SECSPERMIN * MINSPERHOUR) {
+	  offsetlen = stringoffset(result + len,
+				   -(zp->z_gmtoff + dstrp->r_stdoff));
+	  if (! offsetlen) {
+	    result[0] = '\0';
+	    return -1;
+	  }
+	  len += offsetlen;
+	}
+	result[len++] = ',';
+	c = stringrule(result + len, dstrp, dstrp->r_stdoff, zp->z_gmtoff);
+	if (c < 0) {
+		result[0] = '\0';
+		return -1;
+	}
+	if (compat < c)
+		compat = c;
+	len += strlen(result + len);
+	result[len++] = ',';
+	c = stringrule(result + len, stdrp, dstrp->r_stdoff, zp->z_gmtoff);
+	if (c < 0) {
+		result[0] = '\0';
+		return -1;
+	}
+	if (compat < c)
+		compat = c;
+	return compat;
+}
+
+static void
+outzone(const struct zone *zpfirst, ptrdiff_t zonecount)
+{
+	register const struct zone *	zp;
+	register struct rule *		rp;
+	register ptrdiff_t		i, j;
+	register bool			usestart, useuntil;
+	register zic_t			starttime, untiltime;
+	register zic_t			gmtoff;
+	register zic_t			stdoff;
+	register zic_t			year;
+	register zic_t			startoff;
+	register bool			startttisstd;
+	register bool			startttisgmt;
+	register int			type;
+	register char *			startbuf;
+	register char *			ab;
+	register char *			envvar;
+	register int			max_abbr_len;
+	register int			max_envvar_len;
+	register bool			prodstic; /* all rules are min to max */
+	register int			compat;
+	register bool			do_extend;
+	register char			version;
+	ptrdiff_t lastatmax = -1;
+	zic_t one = 1;
+	zic_t y2038_boundary = one << 31;
+	zic_t max_year0;
+
+	max_abbr_len = 2 + max_format_len + max_abbrvar_len;
+	max_envvar_len = 2 * max_abbr_len + 5 * 9;
+	startbuf = emalloc(max_abbr_len + 1);
+	ab = emalloc(max_abbr_len + 1);
+	envvar = emalloc(max_envvar_len + 1);
+	INITIALIZE(untiltime);
+	INITIALIZE(starttime);
+	/*
+	** Now. . .finally. . .generate some useful data!
+	*/
+	timecnt = 0;
+	typecnt = 0;
+	charcnt = 0;
+	prodstic = zonecount == 1;
+	/*
+	** Thanks to Earl Chew
+	** for noting the need to unconditionally initialize startttisstd.
+	*/
+	startttisstd = false;
+	startttisgmt = false;
+	min_year = max_year = EPOCH_YEAR;
+	if (leapseen) {
+		updateminmax(leapminyear);
+		updateminmax(leapmaxyear + (leapmaxyear < ZIC_MAX));
+	}
+	for (i = 0; i < zonecount; ++i) {
+		zp = &zpfirst[i];
+		if (i < zonecount - 1)
+			updateminmax(zp->z_untilrule.r_loyear);
+		for (j = 0; j < zp->z_nrules; ++j) {
+			rp = &zp->z_rules[j];
+			if (rp->r_lowasnum)
+				updateminmax(rp->r_loyear);
+			if (rp->r_hiwasnum)
+				updateminmax(rp->r_hiyear);
+			if (rp->r_lowasnum || rp->r_hiwasnum)
+				prodstic = false;
+		}
+	}
+	/*
+	** Generate lots of data if a rule can't cover all future times.
+	*/
+	compat = stringzone(envvar, zpfirst, zonecount);
+	version = compat < 2013 ? ZIC_VERSION_PRE_2013 : ZIC_VERSION;
+	do_extend = compat < 0 || compat == YEAR_BY_YEAR_ZONE;
+	if (noise) {
+		if (!*envvar)
+			warning("%s %s",
+				_("no POSIX environment variable for zone"),
+				zpfirst->z_name);
+		else if (compat != 0 && compat != YEAR_BY_YEAR_ZONE) {
+			/* Circa-COMPAT clients, and earlier clients, might
+			   not work for this zone when given dates before
+			   1970 or after 2038.  */
+			warning(_("%s: pre-%d clients may mishandle"
+				  " distant timestamps"),
+				zpfirst->z_name, compat);
+		}
+	}
+	if (do_extend) {
+		/*
+		** Search through a couple of extra years past the obvious
+		** 400, to avoid edge cases.  For example, suppose a non-POSIX
+		** rule applies from 2012 onwards and has transitions in March
+		** and September, plus some one-off transitions in November
+		** 2013.  If zic looked only at the last 400 years, it would
+		** set max_year=2413, with the intent that the 400 years 2014
+		** through 2413 will be repeated.  The last transition listed
+		** in the tzfile would be in 2413-09, less than 400 years
+		** after the last one-off transition in 2013-11.  Two years
+		** might be overkill, but with the kind of edge cases
+		** available we're not sure that one year would suffice.
+		*/
+		enum { years_of_observations = YEARSPERREPEAT + 2 };
+
+		if (min_year >= ZIC_MIN + years_of_observations)
+			min_year -= years_of_observations;
+		else	min_year = ZIC_MIN;
+		if (max_year <= ZIC_MAX - years_of_observations)
+			max_year += years_of_observations;
+		else	max_year = ZIC_MAX;
+		/*
+		** Regardless of any of the above,
+		** for a "proDSTic" zone which specifies that its rules
+		** always have and always will be in effect,
+		** we only need one cycle to define the zone.
+		*/
+		if (prodstic) {
+			min_year = 1900;
+			max_year = min_year + years_of_observations;
+		}
+	}
+	/*
+	** For the benefit of older systems,
+	** generate data from 1900 through 2038.
+	*/
+	if (min_year > 1900)
+		min_year = 1900;
+	max_year0 = max_year;
+	if (max_year < 2038)
+		max_year = 2038;
+	for (i = 0; i < zonecount; ++i) {
+		/*
+		** A guess that may well be corrected later.
+		*/
+		stdoff = 0;
+		zp = &zpfirst[i];
+		usestart = i > 0 && (zp - 1)->z_untiltime > early_time;
+		useuntil = i < (zonecount - 1);
+		if (useuntil && zp->z_untiltime <= early_time)
+			continue;
+		gmtoff = zp->z_gmtoff;
+		eat(zp->z_filename, zp->z_linenum);
+		*startbuf = '\0';
+		startoff = zp->z_gmtoff;
+		if (zp->z_nrules == 0) {
+			stdoff = zp->z_stdoff;
+			doabbr(startbuf, zp, NULL, zp->z_isdst, stdoff, false);
+			type = addtype(oadd(zp->z_gmtoff, stdoff),
+				startbuf, zp->z_isdst, startttisstd,
+				startttisgmt);
+			if (usestart) {
+				addtt(starttime, type);
+				usestart = false;
+			} else	addtt(early_time, type);
+		} else for (year = min_year; year <= max_year; ++year) {
+			if (useuntil && year > zp->z_untilrule.r_hiyear)
+				break;
+			/*
+			** Mark which rules to do in the current year.
+			** For those to do, calculate rpytime(rp, year);
+			*/
+			for (j = 0; j < zp->z_nrules; ++j) {
+				rp = &zp->z_rules[j];
+				eats(zp->z_filename, zp->z_linenum,
+					rp->r_filename, rp->r_linenum);
+				rp->r_todo = year >= rp->r_loyear &&
+						year <= rp->r_hiyear &&
+						yearistype(year, rp->r_yrtype);
+				if (rp->r_todo) {
+					rp->r_temp = rpytime(rp, year);
+					rp->r_todo
+					  = (rp->r_temp < y2038_boundary
+					     || year <= max_year0);
+				}
+			}
+			for ( ; ; ) {
+				register ptrdiff_t k;
+				register zic_t	jtime, ktime;
+				register zic_t	offset;
+
+				INITIALIZE(ktime);
+				if (useuntil) {
+					/*
+					** Turn untiltime into UT
+					** assuming the current gmtoff and
+					** stdoff values.
+					*/
+					untiltime = zp->z_untiltime;
+					if (!zp->z_untilrule.r_todisgmt)
+						untiltime = tadd(untiltime,
+							-gmtoff);
+					if (!zp->z_untilrule.r_todisstd)
+						untiltime = tadd(untiltime,
+							-stdoff);
+				}
+				/*
+				** Find the rule (of those to do, if any)
+				** that takes effect earliest in the year.
+				*/
+				k = -1;
+				for (j = 0; j < zp->z_nrules; ++j) {
+					rp = &zp->z_rules[j];
+					if (!rp->r_todo)
+						continue;
+					eats(zp->z_filename, zp->z_linenum,
+						rp->r_filename, rp->r_linenum);
+					offset = rp->r_todisgmt ? 0 : gmtoff;
+					if (!rp->r_todisstd)
+						offset = oadd(offset, stdoff);
+					jtime = rp->r_temp;
+					if (jtime == min_time ||
+						jtime == max_time)
+							continue;
+					jtime = tadd(jtime, -offset);
+					if (k < 0 || jtime < ktime) {
+						k = j;
+						ktime = jtime;
+					} else if (jtime == ktime) {
+					  char const *dup_rules_msg =
+					    _("two rules for same instant");
+					  eats(zp->z_filename, zp->z_linenum,
+					       rp->r_filename, rp->r_linenum);
+					  warning("%s", dup_rules_msg);
+					  rp = &zp->z_rules[k];
+					  eats(zp->z_filename, zp->z_linenum,
+					       rp->r_filename, rp->r_linenum);
+					  error("%s", dup_rules_msg);
+					}
+				}
+				if (k < 0)
+					break;	/* go on to next year */
+				rp = &zp->z_rules[k];
+				rp->r_todo = false;
+				if (useuntil && ktime >= untiltime)
+					break;
+				stdoff = rp->r_stdoff;
+				if (usestart && ktime == starttime)
+					usestart = false;
+				if (usestart) {
+					if (ktime < starttime) {
+						startoff = oadd(zp->z_gmtoff,
+							stdoff);
+						doabbr(startbuf, zp,
+							rp->r_abbrvar,
+							rp->r_isdst,
+							rp->r_stdoff,
+							false);
+						continue;
+					}
+					if (*startbuf == '\0' &&
+						startoff == oadd(zp->z_gmtoff,
+						stdoff)) {
+							doabbr(startbuf,
+								zp,
+								rp->r_abbrvar,
+								rp->r_isdst,
+								rp->r_stdoff,
+								false);
+					}
+				}
+				eats(zp->z_filename, zp->z_linenum,
+					rp->r_filename, rp->r_linenum);
+				doabbr(ab, zp, rp->r_abbrvar,
+				       rp->r_isdst, rp->r_stdoff, false);
+				offset = oadd(zp->z_gmtoff, rp->r_stdoff);
+				type = addtype(offset, ab, rp->r_isdst,
+					rp->r_todisstd, rp->r_todisgmt);
+				if (rp->r_hiyear == ZIC_MAX
+				    && ! (0 <= lastatmax
+					  && ktime < attypes[lastatmax].at))
+				  lastatmax = timecnt;
+				addtt(ktime, type);
+			}
+		}
+		if (usestart) {
+			if (*startbuf == '\0' &&
+				zp->z_format != NULL &&
+				strchr(zp->z_format, '%') == NULL &&
+				strchr(zp->z_format, '/') == NULL)
+					strcpy(startbuf, zp->z_format);
+			eat(zp->z_filename, zp->z_linenum);
+			if (*startbuf == '\0')
+error(_("can't determine time zone abbreviation to use just after until time"));
+			else	addtt(starttime,
+					addtype(startoff, startbuf,
+						startoff != zp->z_gmtoff,
+						startttisstd,
+						startttisgmt));
+		}
+		/*
+		** Now we may get to set starttime for the next zone line.
+		*/
+		if (useuntil) {
+			startttisstd = zp->z_untilrule.r_todisstd;
+			startttisgmt = zp->z_untilrule.r_todisgmt;
+			starttime = zp->z_untiltime;
+			if (!startttisstd)
+				starttime = tadd(starttime, -stdoff);
+			if (!startttisgmt)
+				starttime = tadd(starttime, -gmtoff);
+		}
+	}
+	if (0 <= lastatmax)
+	  attypes[lastatmax].dontmerge = true;
+	if (do_extend) {
+		/*
+		** If we're extending the explicitly listed observations
+		** for 400 years because we can't fill the POSIX-TZ field,
+		** check whether we actually ended up explicitly listing
+		** observations through that period.  If there aren't any
+		** near the end of the 400-year period, add a redundant
+		** one at the end of the final year, to make it clear
+		** that we are claiming to have definite knowledge of
+		** the lack of transitions up to that point.
+		*/
+		struct rule xr;
+		struct attype *lastat;
+		xr.r_month = TM_JANUARY;
+		xr.r_dycode = DC_DOM;
+		xr.r_dayofmonth = 1;
+		xr.r_tod = 0;
+		for (lastat = &attypes[0], i = 1; i < timecnt; i++)
+			if (attypes[i].at > lastat->at)
+				lastat = &attypes[i];
+		if (lastat->at < rpytime(&xr, max_year - 1)) {
+			addtt(rpytime(&xr, max_year + 1), typecnt-1);
+			attypes[timecnt - 1].dontmerge = true;
+		}
+	}
+	writezone(zpfirst->z_name, envvar, version);
+	free(startbuf);
+	free(ab);
+	free(envvar);
+}
+
+static void
+addtt(zic_t starttime, int type)
+{
+	if (starttime <= early_time
+	    || (timecnt == 1 && attypes[0].at < early_time)) {
+		gmtoffs[0] = gmtoffs[type];
+		isdsts[0] = isdsts[type];
+		ttisstds[0] = ttisstds[type];
+		ttisgmts[0] = ttisgmts[type];
+		if (abbrinds[type] != 0)
+			strcpy(chars, &chars[abbrinds[type]]);
+		abbrinds[0] = 0;
+		charcnt = strlen(chars) + 1;
+		typecnt = 1;
+		timecnt = 0;
+		type = 0;
+	}
+	attypes = growalloc(attypes, sizeof *attypes, timecnt, &timecnt_alloc);
+	attypes[timecnt].at = starttime;
+	attypes[timecnt].dontmerge = false;
+	attypes[timecnt].type = type;
+	++timecnt;
+}
+
+static int
+addtype(zic_t gmtoff, char const *abbr, bool isdst, bool ttisstd, bool ttisgmt)
+{
+	register int	i, j;
+
+	/*
+	** See if there's already an entry for this zone type.
+	** If so, just return its index.
+	*/
+	for (i = 0; i < typecnt; ++i) {
+		if (gmtoff == gmtoffs[i] && isdst == isdsts[i] &&
+			strcmp(abbr, &chars[abbrinds[i]]) == 0 &&
+			ttisstd == ttisstds[i] &&
+			ttisgmt == ttisgmts[i])
+				return i;
+	}
+	/*
+	** There isn't one; add a new one, unless there are already too
+	** many.
+	*/
+	if (typecnt >= TZ_MAX_TYPES) {
+		error(_("too many local time types"));
+		exit(EXIT_FAILURE);
+	}
+	if (! (-1L - 2147483647L <= gmtoff && gmtoff <= 2147483647L)) {
+		error(_("UT offset out of range"));
+		exit(EXIT_FAILURE);
+	}
+	gmtoffs[i] = gmtoff;
+	isdsts[i] = isdst;
+	ttisstds[i] = ttisstd;
+	ttisgmts[i] = ttisgmt;
+
+	for (j = 0; j < charcnt; ++j)
+		if (strcmp(&chars[j], abbr) == 0)
+			break;
+	if (j == charcnt)
+		newabbr(abbr);
+	abbrinds[i] = j;
+	++typecnt;
+	return i;
+}
+
+static void
+leapadd(zic_t t, bool positive, int rolling, int count)
+{
+	register int	i, j;
+
+	if (leapcnt + (positive ? count : 1) > TZ_MAX_LEAPS) {
+		error(_("too many leap seconds"));
+		exit(EXIT_FAILURE);
+	}
+	for (i = 0; i < leapcnt; ++i)
+		if (t <= trans[i])
+			break;
+	do {
+		for (j = leapcnt; j > i; --j) {
+			trans[j] = trans[j - 1];
+			corr[j] = corr[j - 1];
+			roll[j] = roll[j - 1];
+		}
+		trans[i] = t;
+		corr[i] = positive ? 1 : -count;
+		roll[i] = rolling;
+		++leapcnt;
+	} while (positive && --count != 0);
+}
+
+static void
+adjleap(void)
+{
+	register int	i;
+	register zic_t	last = 0;
+	register zic_t	prevtrans = 0;
+
+	/*
+	** propagate leap seconds forward
+	*/
+	for (i = 0; i < leapcnt; ++i) {
+		if (trans[i] - prevtrans < 28 * SECSPERDAY) {
+		  error(_("Leap seconds too close together"));
+		  exit(EXIT_FAILURE);
+		}
+		prevtrans = trans[i];
+		trans[i] = tadd(trans[i], last);
+		last = corr[i] += last;
+	}
+}
+
+static char *
+shellquote(char *b, char const *s)
+{
+  *b++ = '\'';
+  while (*s) {
+    if (*s == '\'')
+      *b++ = '\'', *b++ = '\\', *b++ = '\'';
+    *b++ = *s++;
+  }
+  *b++ = '\'';
+  return b;
+}
+
+static bool
+yearistype(zic_t year, const char *type)
+{
+	char *buf;
+	char *b;
+	int result;
+
+	if (type == NULL || *type == '\0')
+		return true;
+	buf = emalloc(1 + 4 * strlen(yitcommand) + 2
+		      + INT_STRLEN_MAXIMUM(zic_t) + 2 + 4 * strlen(type) + 2);
+	b = shellquote(buf, yitcommand);
+	*b++ = ' ';
+	b += sprintf(b, "%"PRIdZIC, year);
+	*b++ = ' ';
+	b = shellquote(b, type);
+	*b = '\0';
+	result = system(buf);
+	if (WIFEXITED(result)) {
+	  int status = WEXITSTATUS(result);
+	  if (status <= 1) {
+	    free(buf);
+	    return status == 0;
+	  }
+	}
+	error(_("Wild result from command execution"));
+	fprintf(stderr, _("%s: command was '%s', result was %d\n"),
+		progname, buf, result);
+	exit(EXIT_FAILURE);
+}
+
+/* Is A a space character in the C locale?  */
+static bool
+is_space(char a)
+{
+	switch (a) {
+	  default:
+		return false;
+	  case ' ': case '\f': case '\n': case '\r': case '\t': case '\v':
+		return true;
+	}
+}
+
+/* Is A an alphabetic character in the C locale?  */
+static bool
+is_alpha(char a)
+{
+	switch (a) {
+	  default:
+		return false;
+	  case 'A': case 'B': case 'C': case 'D': case 'E': case 'F': case 'G':
+	  case 'H': case 'I': case 'J': case 'K': case 'L': case 'M': case 'N':
+	  case 'O': case 'P': case 'Q': case 'R': case 'S': case 'T': case 'U':
+	  case 'V': case 'W': case 'X': case 'Y': case 'Z':
+	  case 'a': case 'b': case 'c': case 'd': case 'e': case 'f': case 'g':
+	  case 'h': case 'i': case 'j': case 'k': case 'l': case 'm': case 'n':
+	  case 'o': case 'p': case 'q': case 'r': case 's': case 't': case 'u':
+	  case 'v': case 'w': case 'x': case 'y': case 'z':
+		return true;
+	}
+}
+
+/* If A is an uppercase character in the C locale, return its lowercase
+   counterpart.  Otherwise, return A.  */
+static char
+lowerit(char a)
+{
+	switch (a) {
+	  default: return a;
+	  case 'A': return 'a'; case 'B': return 'b'; case 'C': return 'c';
+	  case 'D': return 'd'; case 'E': return 'e'; case 'F': return 'f';
+	  case 'G': return 'g'; case 'H': return 'h'; case 'I': return 'i';
+	  case 'J': return 'j'; case 'K': return 'k'; case 'L': return 'l';
+	  case 'M': return 'm'; case 'N': return 'n'; case 'O': return 'o';
+	  case 'P': return 'p'; case 'Q': return 'q'; case 'R': return 'r';
+	  case 'S': return 's'; case 'T': return 't'; case 'U': return 'u';
+	  case 'V': return 'v'; case 'W': return 'w'; case 'X': return 'x';
+	  case 'Y': return 'y'; case 'Z': return 'z';
+	}
+}
+
+/* case-insensitive equality */
+static bool
+ciequal(register const char *ap, register const char *bp)
+{
+	while (lowerit(*ap) == lowerit(*bp++))
+		if (*ap++ == '\0')
+			return true;
+	return false;
+}
+
+static bool
+itsabbr(register const char *abbr, register const char *word)
+{
+	if (lowerit(*abbr) != lowerit(*word))
+		return false;
+	++word;
+	while (*++abbr != '\0')
+		do {
+			if (*word == '\0')
+				return false;
+		} while (lowerit(*word++) != lowerit(*abbr));
+	return true;
+}
+
+/* Return true if ABBR is an initial prefix of WORD, ignoring ASCII case.  */
+
+static bool
+ciprefix(char const *abbr, char const *word)
+{
+  do
+    if (!*abbr)
+      return true;
+  while (lowerit(*abbr++) == lowerit(*word++));
+
+  return false;
+}
+
+static const struct lookup *
+byword(const char *word, const struct lookup *table)
+{
+	register const struct lookup *	foundlp;
+	register const struct lookup *	lp;
+
+	if (word == NULL || table == NULL)
+		return NULL;
+
+	/* If TABLE is LASTS and the word starts with "last" followed
+	   by a non-'-', skip the "last" and look in WDAY_NAMES instead.
+	   Warn about any usage of the undocumented prefix "last-".  */
+	if (table == lasts && ciprefix("last", word) && word[4]) {
+	  if (word[4] == '-')
+	    warning(_("\"%s\" is undocumented; use \"last%s\" instead"),
+		    word, word + 5);
+	  else {
+	    word += 4;
+	    table = wday_names;
+	  }
+	}
+
+	/*
+	** Look for exact match.
+	*/
+	for (lp = table; lp->l_word != NULL; ++lp)
+		if (ciequal(word, lp->l_word))
+			return lp;
+	/*
+	** Look for inexact match.
+	*/
+	foundlp = NULL;
+	for (lp = table; lp->l_word != NULL; ++lp)
+		if (ciprefix(word, lp->l_word)) {
+			if (foundlp == NULL)
+				foundlp = lp;
+			else	return NULL;	/* multiple inexact matches */
+		}
+
+	/* Warn about any backward-compatibility issue with pre-2017c zic.  */
+	if (foundlp) {
+	  bool pre_2017c_match = false;
+	  for (lp = table; lp->l_word; lp++)
+	    if (itsabbr(word, lp->l_word)) {
+	      if (pre_2017c_match) {
+		warning(_("\"%s\" is ambiguous in pre-2017c zic"), word);
+		break;
+	      }
+	      pre_2017c_match = true;
+	    }
+	}
+
+	return foundlp;
+}
+
+static char **
+getfields(register char *cp)
+{
+	register char *		dp;
+	register char **	array;
+	register int		nsubs;
+
+	if (cp == NULL)
+		return NULL;
+	array = emalloc(size_product(strlen(cp) + 1, sizeof *array));
+	nsubs = 0;
+	for ( ; ; ) {
+		while (is_space(*cp))
+				++cp;
+		if (*cp == '\0' || *cp == '#')
+			break;
+		array[nsubs++] = dp = cp;
+		do {
+			if ((*dp = *cp++) != '"')
+				++dp;
+			else while ((*dp = *cp++) != '"')
+				if (*dp != '\0')
+					++dp;
+				else {
+				  error(_("Odd number of quotation marks"));
+				  exit(EXIT_FAILURE);
+				}
+		} while (*cp && *cp != '#' && !is_space(*cp));
+		if (is_space(*cp))
+			++cp;
+		*dp = '\0';
+	}
+	array[nsubs] = NULL;
+	return array;
+}
+
+static _Noreturn void
+time_overflow(void)
+{
+  error(_("time overflow"));
+  exit(EXIT_FAILURE);
+}
+
+static ATTRIBUTE_PURE zic_t
+oadd(zic_t t1, zic_t t2)
+{
+	if (t1 < 0 ? t2 < ZIC_MIN - t1 : ZIC_MAX - t1 < t2)
+	  time_overflow();
+	return t1 + t2;
+}
+
+static ATTRIBUTE_PURE zic_t
+tadd(zic_t t1, zic_t t2)
+{
+  if (t1 < 0) {
+    if (t2 < min_time - t1) {
+      if (t1 != min_time)
+	time_overflow();
+      return min_time;
+    }
+  } else {
+    if (max_time - t1 < t2) {
+      if (t1 != max_time)
+	time_overflow();
+      return max_time;
+    }
+  }
+  return t1 + t2;
+}
+
+/*
+** Given a rule, and a year, compute the date (in seconds since January 1,
+** 1970, 00:00 LOCAL time) in that year that the rule refers to.
+*/
+
+static zic_t
+rpytime(const struct rule *rp, zic_t wantedy)
+{
+	register int	m, i;
+	register zic_t	dayoff;			/* with a nod to Margaret O. */
+	register zic_t	t, y;
+
+	if (wantedy == ZIC_MIN)
+		return min_time;
+	if (wantedy == ZIC_MAX)
+		return max_time;
+	dayoff = 0;
+	m = TM_JANUARY;
+	y = EPOCH_YEAR;
+	while (wantedy != y) {
+		if (wantedy > y) {
+			i = len_years[isleap(y)];
+			++y;
+		} else {
+			--y;
+			i = -len_years[isleap(y)];
+		}
+		dayoff = oadd(dayoff, i);
+	}
+	while (m != rp->r_month) {
+		i = len_months[isleap(y)][m];
+		dayoff = oadd(dayoff, i);
+		++m;
+	}
+	i = rp->r_dayofmonth;
+	if (m == TM_FEBRUARY && i == 29 && !isleap(y)) {
+		if (rp->r_dycode == DC_DOWLEQ)
+			--i;
+		else {
+			error(_("use of 2/29 in non leap-year"));
+			exit(EXIT_FAILURE);
+		}
+	}
+	--i;
+	dayoff = oadd(dayoff, i);
+	if (rp->r_dycode == DC_DOWGEQ || rp->r_dycode == DC_DOWLEQ) {
+		register zic_t	wday;
+
+#define LDAYSPERWEEK	((zic_t) DAYSPERWEEK)
+		wday = EPOCH_WDAY;
+		/*
+		** Don't trust mod of negative numbers.
+		*/
+		if (dayoff >= 0)
+			wday = (wday + dayoff) % LDAYSPERWEEK;
+		else {
+			wday -= ((-dayoff) % LDAYSPERWEEK);
+			if (wday < 0)
+				wday += LDAYSPERWEEK;
+		}
+		while (wday != rp->r_wday)
+			if (rp->r_dycode == DC_DOWGEQ) {
+				dayoff = oadd(dayoff, 1);
+				if (++wday >= LDAYSPERWEEK)
+					wday = 0;
+				++i;
+			} else {
+				dayoff = oadd(dayoff, -1);
+				if (--wday < 0)
+					wday = LDAYSPERWEEK - 1;
+				--i;
+			}
+		if (i < 0 || i >= len_months[isleap(y)][m]) {
+			if (noise)
+				warning(_("rule goes past start/end of month; \
+will not work with pre-2004 versions of zic"));
+		}
+	}
+	if (dayoff < min_time / SECSPERDAY)
+		return min_time;
+	if (dayoff > max_time / SECSPERDAY)
+		return max_time;
+	t = (zic_t) dayoff * SECSPERDAY;
+	return tadd(t, rp->r_tod);
+}
+
+static void
+newabbr(const char *string)
+{
+	register int	i;
+
+	if (strcmp(string, GRANDPARENTED) != 0) {
+		register const char *	cp;
+		const char *		mp;
+
+		cp = string;
+		mp = NULL;
+		while (is_alpha(*cp) || ('0' <= *cp && *cp <= '9')
+		       || *cp == '-' || *cp == '+')
+				++cp;
+		if (noise && cp - string < 3)
+		  mp = _("time zone abbreviation has fewer than 3 characters");
+		if (cp - string > ZIC_MAX_ABBR_LEN_WO_WARN)
+		  mp = _("time zone abbreviation has too many characters");
+		if (*cp != '\0')
+mp = _("time zone abbreviation differs from POSIX standard");
+		if (mp != NULL)
+			warning("%s (%s)", mp, string);
+	}
+	i = strlen(string) + 1;
+	if (charcnt + i > TZ_MAX_CHARS) {
+		error(_("too many, or too long, time zone abbreviations"));
+		exit(EXIT_FAILURE);
+	}
+	strcpy(&chars[charcnt], string);
+	charcnt += i;
+}
+
+/* Ensure that the directories of ARGNAME exist, by making any missing
+   ones.  If ANCESTORS, do this only for ARGNAME's ancestors; otherwise,
+   do it for ARGNAME too.  Exit with failure if there is trouble.
+   Do not consider an existing non-directory to be trouble.  */
+static void
+mkdirs(char const *argname, bool ancestors)
+{
+	register char *	name;
+	register char *	cp;
+
+	cp = name = ecpyalloc(argname);
+
+	/* On MS-Windows systems, do not worry about drive letters or
+	   backslashes, as this should suffice in practice.  Time zone
+	   names do not use drive letters and backslashes.  If the -d
+	   option of zic does not name an already-existing directory,
+	   it can use slashes to separate the already-existing
+	   ancestor prefix from the to-be-created subdirectories.  */
+
+	/* Do not mkdir a root directory, as it must exist.  */
+	while (*cp == '/')
+	  cp++;
+
+	while (cp && ((cp = strchr(cp, '/')) || !ancestors)) {
+		if (cp)
+		  *cp = '\0';
+		/*
+		** Try to create it.  It's OK if creation fails because
+		** the directory already exists, perhaps because some
+		** other process just created it.  For simplicity do
+		** not check first whether it already exists, as that
+		** is checked anyway if the mkdir fails.
+		*/
+		if (mkdir(name, MKDIR_UMASK) != 0) {
+			/* For speed, skip itsdir if errno == EEXIST.  Since
+			   mkdirs is called only after open fails with ENOENT
+			   on a subfile, EEXIST implies itsdir here.  */
+			int err = errno;
+			if (err != EEXIST && !itsdir(name)) {
+				error(_("%s: Can't create directory %s: %s"),
+				      progname, name, strerror(err));
+				exit(EXIT_FAILURE);
+			}
+		}
+		if (cp)
+		  *cp++ = '/';
+	}
+	free(name);
+}