* lib/boot-time-aux.h (get_linux_uptime):
* lib/boot-time.c (UT_USER):
* lib/nproc.c (num_processors_ignoring_omp):
* lib/readutmp.h (WTMP_FILE):
* m4/readutmp.m4 (gl_READUTMP):
* m4/stdint.m4: Update from Gnulib.

Simplify Emacs proper by using Gnulib’s boot-time module
instead of doing it all by hand.  This should port Emacs
better to obscurish hosts, as Bruno Haible has merged the
best of Emacs’s and Gnulib’s boot-time gathering.
* lib/boot-time-aux.h, lib/boot-time.c, lib/boot-time.h:
* lib/readutmp.h, m4/readutmp.m4: New files, copied from Gnulib.
* admin/merge-gnulib (GNULIB_MODULES): Add boot-time.
* configure.ac: Do not check for utmp.h;
the boot-time module now does this.
(BOOT_TIME_FILE): Remove; no longer used.
* lib/gnulib.mk.in, m4/gnulib-comp.m4: Regenerate.
* src/filelock.c [__FreeBSD__]: Do not include <sys/sysctl.h>.
[HAVE_UTMP_H]: Do not include utmp.h.
Include boot-time instead: boot-time does the work now.
(BOOT_TIME) [HAVE_ANDROID && !ANDROID_STUBIFY]: Don’t undef.
(WTMP_FILE): Don’t define.
(boot_time, boot_time_initialized, get_boot_time_1, get_boot_time):
Remove.
(get_boot_sec): New function that simply calls Gnulib get_boot_time.
(lock_file_1, current_lock_owner): Use get_boot_sec instead
of get_boot_time.

It’s not worth the porting hassle, and as the glibc manual says,
“this function is generally a poor choice for processing strings”.
* admin/merge-gnulib (GNULIB_MODULES): Remove stpncpy.
* exec/configure.ac: Do not check for stpncpy.
* exec/exec.c (rpl_stpncpy, stpncpy): Remove this replacement.
(exec_0): Properly clear buffer1.  Use memcpy instead of
stpncpy to add the trailing name.  This code is clearly
still suboptimal but efficiency is not that important here
and I tried to minimize the change.
* lib/gnulib.mk.in, m4/gnulib-comp.m4: Regenerate.

* m4, lib: Update from Gnulib.

* msdos/sedlibmk.inp: Remove variables deleted as part of previous
change.

* admin/merge-gnulib (GNULIB_MODULES): Remove vasprintf and
printf-posix.

* configure.ac (gl_STDLIB_H): Replace this, not gt_LOCALE_FR_UTF8,
as this lets us also omit MB_CUR_MAX checking that will never be
executed, and also lets us remove testing for ecvt, fcvt, gcvt
that Emacs doesn’t need.
(AC_C_RESTRICT): Invoke explicitly, as Emacs uses ‘restrict’
directly.  Also, simplifies the replacement for gl_STDLIB_H, which
would otherwise need to AC_REQUIRE AC_C_RESTRICT.
* lib/gnulib.mk.in: Regenerate via admin/merge-gnulib.

* lib/vasnprintf.c (VASNPRINTF):
* m4/printf.m4 (gl_SWPRINTF_WORKS):
(gl_SWPRINTF_DIRECTIVE_LA):
* m4/vasnprintf.m4 (gl_PREREQ_PRINTF_PARSE):