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.
From ChangeLog
* VERSION: 20180222
Merge with NetBSD make, pick up
o parse.c: avoid calling sysconf for every call to loadfile
* VERSION: 20180218
Merge with NetBSD make, pick up
o var.c: Var_Set handle NULL value anytime.
* VERSION: 20180212
Merge with NetBSD make, pick up
o parse.c: do not treat .info as warning with -W
* VERSION: 20171207
Merge with NetBSD make, pick up
o var.c: Var_Append use Var_Set if var not previously set
so that VAR_CMD is handled correctly.
Add a suitable unit-test.
* VERSION: 20171126
* aclocal.m4: use AC_LINK_IFELSE for AC_C___ATTRIBUTE__
since AC_TRY_COMPILE puts input inside main()
which upsets modern compilers.
* VERSION: 20171118
Merge with NetBSD make, pick up
o var.c: do not append to variable set on command line
add unit-test to catch this.
Interesting changes:
o meta.c: move handling of .MAKE.META.IGNORE_* to meta_ignore()
so we can call it before adding entries to missingFiles.
Thus we do not track files we have been told to ignore.
o meta_oodate: apply .MAKE.META.IGNORE_FILTER (if defined) to
pathnames, and skip if the expansion is empty.
Useful for dirdeps.mk when checking DIRDEPS_CACHE.
o meta.c: remove all missingFiles entries that match a deleted
dir.
o main.c: set .ERROR_CMD if possible.
Interesting changes (from ChangeLog):
o meta.c: ignore paths that match .MAKE.META.IGNORE_PATTERNS
this is useful for gcov builds.
o propagate errors from filemon(4).
o meta.c: apply realpath() before matching against metaIgnorePaths
o allow makefile to set .MAKE.JOBS
