Relevant changes see ChangeLog for details:
Add support for ${.SUFFIXES} as read-only variable.
Fix memory leak in cond.c
Punt on write errors - ENOSPC etc.
Lots of code refactoring, rework to reduce memory allocations.
More unit-tests.
o allow env var MAKE_OBJDIR_CHECK_WRITABLE=no to skip writable
checks in InitObjdir. Explicit .OBJDIR target always allows
read-only directory.
o Fix building and unit-tests on non-BSD.
o More code cleanup and refactoring.
o More unit tests
Lots of new unit-tests increase code coverage.
Lots of refactoring, cleanup and simlpification to reduce
code size.
Fixes for Bug 223564 and 245807
Updates to dirdeps.mk and meta2deps.py
Changes since 20181221 are mostly portability related
hence the large gap in versions imported.
There are however some bug fixes, and a rework of filemon handling.
In NetBSD make/filemon/filemon_ktrace.c allows use of fktrace
and elimination of filemon(4) which has not had the TLC it needs.
FreeBSD filemon(4) is in much better shape, so bmake/filemon/filemon_dev.c
allows use of that, with a bit less overhead than the ktrace model.
Summary of changes from ChangeLog
o str.c: empty string does not match % pattern
plus unit-test changes
o var.c: import handling of old sysV style modifier using '%'
o str.c: refactor brk_string
o meta.c: meta_oodate, CHECK_VALID_META is too aggressive for CMD
a blank command is perfectly valid.
o meta.c: meta_oodate, check for corrupted meta file
earlier and more often.
* meta.c: meta_compat_parent check for USE_FILEMON
patch from Soeren Tempel
o meta.c: fix compat mode, need to call meta_job_output()
o job.c: extra fds for meta mode not needed if using filemon_dev
o meta.c: avoid passing NULL to filemon_*() when meta_needed()
returns FALSE.
o filemon/filemon_{dev,ktrace}.c: allow selection of
filemon implementation. filemon_dev.c uses the kernel module
while filemon_ktrace.c leverages the fktrace api available in
NetBSD. filemon_ktrace.c can hopefully form the basis for
adding support for other tracing mechanisms such as strace on
Linux.
o meta.c: when target is out-of-date per normal make rules
record value of .OODATE in meta file.
o parse.c: don't pass NULL to realpath(3)
some versions cannot handle it.
o parse.c: ParseDoDependency: free paths rather than assert
plus more unit-tests
Interesting items from ChangeLog:
o cached_realpath(): avoid hitting filesystem more than necessary.
o meta.c: refactor need_meta decision, add knobs for
missing meta file and filemon data wrt out-of-datedness.
o meta.c: missing filemon data is only relevant if we read a
meta file.
Also do not return oodate for a missing metafile if gn->path
points to .CURDIR
