Import bmake-20240108

Interesting/relevant changes since bmake-20230909

• VERSION (_MAKE_VERSION): 20240106

Merge with NetBSD make, pick up
o fix duplicate progname when reporting an unknown target
o unit tests for Cmd_Exec using temp file

• VERSION (_MAKE_VERSION): 20240105

Merge with NetBSD make, pick up
o main.c: Cmd_Exec write cmd to a file if too big
avoid blowing commandline/env limits

• VERSION (_MAKE_VERSION): 20240101

o util.c: flesh out more of strftime

• configure.in: add --with-bmake-strftime

it is not a full implementation but enough to pass all
the unit-tests.

• parse.c: LoadFile do not append \n to empty buffer.

• VERSION (_MAKE_VERSION): 20231230

Merge with NetBSD make, pick up
o simplify memory allocation for string buffers
o fix declared types of list nodes
o suff.c: clean up freeing of suffixes
o var.c: simplify debug message for the ':@var@...@' modifier
clean up variable handling

• VERSION (_MAKE_VERSION): 20231226

Merge with NetBSD make, pick up
o compat.c: ensure make's output is correctly ordered with that of
the target when not going to a tty
o main.c: check for shellPath whether to call Shell_Init()

• VERSION (_MAKE_VERSION): 20231224

Merge with NetBSD make, pick up
o compat.c: check for shellPath whether to call Shell_Init()
tweak the unit test to detect the bug thus fixed.
o make.1: do not claim .SHELL is only used by jobs mode.

• VERSION (_MAKE_VERSION): 20231220

Merge with NetBSD make, pick up
o str.c: speed up pattern matching in the ':M' modifier
o var.c: fix confusing debug logging when deleting a variable
use consistent debug messages style when ignoring variables

• VERSION (_MAKE_VERSION): 20231210

Merge with NetBSD make, pick up
o var.c: avoid segfault on empty :C match expression
explain in debug log why variable assignment is ignored.

• VERSION (_MAKE_VERSION): 20231208

Merge with NetBSD make, pick up
o var.c: ensure fromCmd is set correctly for variables set on
command line.

• VERSION (_MAKE_VERSION): 20231124

Merge with NetBSD make, pick up
o main.c: cleanup processing of -j
fix lint warning about strchr
o var.c: more accurate error message for invalid ':mtime' argument
cleanup :[...] modifier
avoid reading beyond substring when comparing
o unit-tests cover all cases of :mtime, test and explain exporting
of variables
o cleanup comments

• bsd.after-import.mk (ECHO_TAG): FreeBSD no longer uses

$FreeBSD$ tag, so avoid adding it.

mk/ChangeLog since bmake-20230909

• dirdeps.mk: for MAKE_VERSION 20240105 we do not have the same

limits on command line length, so skip export of lists to env.

• jobs.mk: avoid C suffix in JOB_MAX_C if factor is floating

point. This keeps JOB_MAX numeric incase another makefile does
comparisons.

• gendirdeps.mk: if META_XTRAS is passed to us, add to META_FILES