Update to 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 variable parsing detects more errors.

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, 24 insertions, 0 deletions

diff --git a/contrib/bmake/unit-tests/opt-query.mk b/contrib/bmake/unit-tests/opt-query.mk
new file mode 100644
index 000000000000..04e605991140
--- /dev/null
+++ b/contrib/bmake/unit-tests/opt-query.mk
@@ -0,0 +1,24 @@
+# $NetBSD: opt-query.mk,v 1.3 2020/08/19 05:13:18 rillig Exp $
+#
+# Tests for the -q command line option.
+#
+# The -q option only looks at the dependencies between the targets.
+# None of the commands in the targets are run, not even those that are
+# prefixed with '+'.
+
+# This command cannot be prevented from being run since it is used at parse
+# time, and any later variable assignments may depend on its result.
+!=	echo 'command during parsing' 1>&2; echo
+
+# None of these commands are run.
+.BEGIN:
+	@echo '$@: hidden command'
+	@+echo '$@: run always'
+
+# None of these commands are run.
+all:
+	@echo '$@: hidden command'
+	@+echo '$@: run always'
+
+# The exit status 1 is because the "all" target has to be made, that is,
+# it is not up-to-date.