Import bmake-20200902vendor/NetBSD/bmake/20200902

Lots of code refactoring, simplification and cleanup.
Lots of new unit-tests providing much higher code coverage.
All courtesy of rillig at netbsd.

Other significant changes:

o new read-only variable .SHELL which provides the path of the shell
  used to run scripts (as defined by  the .SHELL target).

o new debug option -dl: LINT mode, does the equivalent of := for all
  variable assignments so that file and line number are reported for
  variable parse errors.

1 files changed, 23 insertions, 0 deletions

diff --git a/unit-tests/archive-suffix.mk b/unit-tests/archive-suffix.mk
new file mode 100755
index 000000000000..9f7fa219c667
--- /dev/null
+++ b/unit-tests/archive-suffix.mk
@@ -0,0 +1,23 @@
+# $NetBSD: archive-suffix.mk,v 1.1 2020/08/29 14:47:26 rillig Exp $
+#
+# Between 2020-08-23 and 2020-08-30, the below code produced an assertion
+# failure in Var_Set_with_flags, triggered by Compat_Make, when setting the
+# .IMPSRC of an archive node to its .TARGET.
+#
+# The code assumed that the .TARGET variable of every node would be set, but
+# but that is not guaranteed.
+#
+# Between 2016-03-15 and 2016-03-16 the behavior of the below code changed.
+# Until 2016-03-15, it remade the target, starting with 2016-03-16 it says
+# "`all' is up to date".
+
+.SUFFIXES:
+.SUFFIXES: .c .o
+
+all:	lib.a(obj1.o)
+
+.c.o:
+	: making $@
+
+obj1.c:
+	: $@