* build-aux/config.guess, lib/regcomp.c, lib/regex.c:
* lib/regex_internal.h, lib/regexec.c: Copy from Gnulib.

This incorporates:
2018-12-16 regex: propagate fix for glibc bug 18040
2018-12-16 obstack, libc-config: Support HP-UX cc in C99 mode
2018-12-15 regex: work around a bug in glibc-2.27 and prior
2018-12-13 localtime-buffer: Avoid endless recursion
* build-aux/config.guess, build-aux/config.sub, lib/cdefs.h:
* lib/gettext.h, lib/localtime-buffer.c, lib/regexec.c, m4/regex.m4:
Copy from Gnulib.

fdatasync is for storage devices, not ttys.
* admin/merge-gnulib (GNULIB_MODULES): Remove fdatasync.
* lib/fdatasync.c, m4/fdatasync.m4: Remove.
* lib-src/Makefile.in (LIB_FDATASYNC):
* src/Makefile.in (LIB_FDATASYNC):
Remove.  All uses removed.
* lib-src/emacsclient.c [!DOS_NT]:
Include <termios.h>, for tcdrain.
* lib-src/emacsclient.c (flush_stdout):
* src/sysdep.c (reset_sys_modes): On ttys, use tcdrain instead
of fdatasync (except don’t use either function if DOS_NT).
* lib/gnulib.mk.in, m4/gnulib-comp.m4: Regenerate.

This incorporates:
2018-11-30 memrchr: port better to clang
2018-11-21 mktime: add libc-config dependency
* build-aux/config.guess, build-aux/config.sub, lib/memrchr.c:
Copy from Gnulib.
* m4/gnulib-comp.m4: Regenerate.

This incorporates:
2018-11-15 mktime: DEBUG_MKTIME cleanup
2018-11-15 mktime: fix non-EOVERFLOW errno handling
2018-11-15 mktime: fix bug with Y2038 DST transition
2018-11-15 mktime: make more room for overflow
2018-11-15 mktime: simplify offset guess
2018-11-15 mktime: new test for mktime failure
2018-11-15 mktime: fix EOVERFLOW bug
2018-11-13 longlong: fix comment typo
* lib/gnulib.mk.in: Regenerate.
* lib/mktime.c, m4/longlong.m4: Copy from Gnulib.

This incorporates:
2018-11-03 nstrftime: simplify test for mktime failure
2018-11-02 gnulib-common.m4: port _Noreturn to C++
2018-10-22 std-gnu11: Support Autoconf versions < 2.64
2018-10-22 Assume Autoconf >= 2.63
2018-10-16 Remove support for Ultrix
2018-10-16 getloadavg: Remove support for ConvexOS
2018-10-16 getloadavg: Remove support for Sony NEWS
2018-10-16 Remove support for Dynix/ptx
2018-10-16 fsusage: Remove support for AIX 3
2018-10-16 fsusage, stat-size, getloadavg: Remove support for AIX PS/2
2018-10-16 getloadavg: Remove support for HP-UX on m68k
2018-10-16 fsusage, mountlist: Remove support for DolphinOS
2018-10-16 getloadavg: Remove support for Alliant FX/2800
2018-10-16 getloadavg: Remove support for tek4300
2018-10-16 getloadavg: Remove support for Ardent
* build-aux/config.guess, build-aux/config.sub, lib/_Noreturn.h:
* lib/fsusage.c, lib/getgroups.c, lib/getloadavg.c:
* lib/nstrftime.c, lib/time.in.h, m4/errno_h.m4:
* m4/fsusage.m4, m4/getgroups.m4, m4/gnulib-common.m4, m4/longlong.m4:
* m4/std-gnu11.m4, m4/stdint.m4:
Copy from Gnulib.
* lib/gnulib.mk.in, m4/gnulib-comp.m4: Regenerate:

This syncs recent refactorings from glibc, and incorporates:
2018-10-15 libc-config: merge from glibc
2018-10-15 regex: depend on libc-config
* .gitignore: Do not ignore m4/_*.m4.
* lib/cdefs.h: New file, copied from Gnulib.
* lib/gnulib.mk.in, m4/gnulib-comp.m4: Regenerate.
* lib/libc-config.h, m4/__inline.m4: New files, copied from Gnulib.
* lib/regcomp.c, lib/regex.c, lib/regex_internal.c:
* lib/regex_internal.h, lib/regexec.c:
Copy from glibc via Gnulib.

This incorporates:
2018-10-05 explicit_bzero: make it possible to namespace
2018-10-04 fcntl: make it possible to namespace
2018-10-01 mkostemp, mkostemps: fix C++ compilation on Mac OS X
2018-09-19 maint: mktime.c now shared with glibc
2018-09-18 file-has-acl: fix test failure on Cygwin 2.9
2018-09-18 gettime: nanotime never existed
* admin/merge-gnulib (AVOIDED_MODULES): Add mkdir.
* doc/misc/texinfo.tex, lib/acl-internal.c, lib/acl-internal.h:
* lib/acl_entries.c, lib/explicit_bzero.c, lib/fcntl.c:
* lib/get-permissions.c, lib/gettime.c, lib/mktime.c:
* lib/set-permissions.c, lib/stdlib.in.h, m4/acl.m4, m4/gettime.m4:
Copy from Gnulib.
* lib/gnulib.mk.in: Regenerate.

Problem reported by T.V Raman in:
https://lists.gnu.org/r/emacs-devel/2018-09/msg00866.html
* Makefile.in (clean, extraclean):
* doc/emacs/Makefile.in (mostlyclean):
* doc/lispintro/Makefile.in (mostlyclean):
* doc/lispref/Makefile.in (mostlyclean):
* doc/misc/Makefile.in (mostlyclean, clean):
* etc/refcards/Makefile (clean):
* lib-src/Makefile.in (mostlyclean, extraclean):
* lib/Makefile.in (clean):
* lwlib/Makefile.in (clean mostlyclean):
* oldXMenu/Makefile.in (clean mostlyclean):
* src/Makefile.in (mostlyclean, extraclean):
* test/Makefile.in (mostlyclean):
Say ‘rm ./*.o’ instead of ‘rm *.o’ to avoid undesirable failure
when a file name begins with ‘-’.

This change was motivated by the desire to remove the weird
dependency of lib-src/profile.o on src/systime.h.  profile.c
included systime.h only for current_timespec, and this
inclusion required systime.h to have #ifdef emacs in multiple
places and complicated further changes I have in mind.
The current_timespec decl belongs in timespec.h anyway,
and the main effect of this change is to move it there.
* lib-src/profile.c (INLINE): Remove.
Include timespec.h, not systime.h.
* lib/gettime.c (gettime): Prefer clock_gettime to nanotime,
and don’t worry about it failing on a CLOCK_REALTIME arg.
POSIX requires it to succeed and I don’t know of any
counterexamples where the fallbacks would work.
(current_timespec): Move here from src/systime.h.
Nowadays it seems to be better to not have this function
be inline.
* lib/timespec.h: Include arg-nonnull.h.
(current_timespec): New declaration.
(gettime, settime): Declare args to be nonnull.
* lib/gettime.c, lib/timespec.h: Copy from Gnulib.
* src/systime.h: Simplify by assuming ‘emacs’ is defined,
which it always is now.
(current_timespec): Move to lib/timespec.h.