This incorporates:
2020-08-25 verify: Avoid warnings when assume(0) is used
* lib/verify.h: Copy from Gnulib.

This incorporates:
* lib/diffseq.h, m4/inttypes.m4: Copy from Gnulib.
* m4/gnulib-comp.m4: Regenerate.

Inspired by a straightforward patch by Bruno Haible.
* admin/merge-gnulib (GNULIB_MODULES): Add sigdescr_np.
* configure.ac: Do not check for sys_siglist or __sys_siglist.
* lib/gnulib.mk.in, m4/gnulib-comp.m4: Regenerate.
* lib/sigdescr_np.c, m4/sigdescr_np.m4: New files, copied from Gnulib.
* src/sysdep.c (sys_siglist, sys_siglist_entries): Remove.
(init_signals): Do not initialize sys_siglist.
(safe_strsignal): Use sigdescr_np instead of sys_siglist.

This incorporates:
2020-08-23 intprops: be consistent about +X vs X+0
2020-08-23 intprops: fix INT_MULTIPLY_WRAPV bit-field bug
2020-08-23 verify: Make assume work on bit field expressions
2020-08-23 libc-config: Improve comments
2020-08-22 verify: Do use __builtin_assume on clang
2020-08-22 sig2str: Add more signals
2020-08-21 sigdescr_np: New module
* lib/cdefs.h, lib/intprops.h, lib/sig2str.c, lib/string.in.h:
* lib/verify.h, m4/string_h.m4: Copy from Gnulib.
* lib/gnulib.mk.in: Regenerate.

This incorporates:
2020-08-20 sigabbrev_np: New module
2020-08-20 stdalign: Fix 32-bit test failures clang versions < 8
2020-08-17 careadlinkat: speedup for GCC 10 with GCC_LINT
2020-08-17 Assume autoconf >= 2.64
* build-aux/config.guess, build-aux/config.sub, lib/careadlinkat.c:
* lib/stdalign.in.h, lib/string.in.h, m4/std-gnu11.m4, m4/string_h.m4:
Copy from Gnulib.
* lib/gnulib.mk.in: Regenerate.

This incorporates:
2020-08-17 verify: avoid __built_assume on Clang
2020-08-17 libc-config: avoid Clang’s __diagnose_if__
* lib/cdefs.h, lib/verify.h: Copy from Gnulib.

This incorporates:
2020-08-16 time_rz: remove unused functions
2020-08-16 time_rz: fix issues with mktime_z failures
2020-08-16 nstrftime: Guide inlining also on clang
2020-08-16 intprops: Avoid bogus warning on clang
2020-08-16 libc-config: Enable __REDIRECT macro also on clang
2020-08-16 regex: Use initializer shorthand syntax also with clang
2020-08-16 regex: Use space optimization also with clang
2020-08-16 Use _Static_assert and static_assert when present on clang
2020-08-16 Use 'throw ()' for optimization in C++ mode also on clang
2020-08-16 stdio: Don't break attribute 'scanf' on clang
2020-08-16 Fix "warning: 'format' attribute ...: rpl_printf"
2020-08-16 Fix "warning: attribute declaration must precede definition"
2020-08-16 Fix undesired warnings
2020-08-16 Don't use Autoconf quadrigraphsxo
2020-08-16 Fix quoting of AC_LANG_PROGRAM arguments
2020-08-16 Assume autoconf >= 2.64
2020-08-15 nstrftime: be more predictable about errno
2020-08-15 canonicalize: Fix autoconf test on MSVC/clang
2020-08-15 Support compiling without -loldnames on native Windows
2020-08-14 mktime, mktime-internal: Remove obsolete code
2020-08-14 Assume tzset exists
* lib/c++defs.h, lib/canonicalize-lgpl.c, lib/cdefs.h, lib/dup2.c:
* lib/fcntl.in.h, lib/getopt-cdefs.in.h, lib/intprops.h, lib/md5.h:
* lib/mktime.c, lib/nstrftime.c, lib/open.c, lib/regcomp.c:
* lib/regex_internal.h, lib/stdio.in.h, lib/stdlib.in.h:
* lib/strftime.h, lib/string.in.h, lib/sys_select.in.h:
* lib/sys_stat.in.h, lib/sys_time.in.h, lib/time.in.h, lib/time_rz.c:
* lib/unistd.in.h, lib/verify.h, m4/00gnulib.m4:
* m4/absolute-header.m4, m4/alloca.m4, m4/canonicalize.m4, m4/dup2.m4:
* m4/fchmodat.m4, m4/fcntl.m4, m4/fdopendir.m4, m4/fpending.m4:
* m4/futimens.m4, m4/getdtablesize.m4, m4/getloadavg.m4:
* m4/gnulib-common.m4, m4/include_next.m4, m4/largefile.m4:
* m4/manywarnings.m4, m4/mktime.m4, m4/nstrftime.m4, m4/open-slash.m4:
* m4/pselect.m4, m4/pthread_sigmask.m4, m4/time_h.m4, m4/utimens.m4:
* m4/utimensat.m4, m4/utimes.m4, m4/warnings.m4:
Copy from Gnulib.
* lib/gnulib.mk.in: Regenerate.

This incorporates:
2020-08-13 sys_random: Work around an uClibc bug
* lib/sys_random.in.h, m4/getrandom.m4, m4/sys_random_h.m4:
Copy from Gnulib.

It wasn’t needed for MinGW after all, no other platform
seems to need it, and it slows down ‘configure’.
* admin/merge-gnulib (GNULIB_MODULES): Remove inttypes.
* m4/gnulib-comp.m4: Regenerate.

This incorporates:
2020-08-12 stdint: port intptr_t to more-recent MinGW
2020-08-11 Use __restrict also on clang
2020-08-11 Use flexible array syntax also on clang
2020-08-11 fcntl: On native Windows, use _setmode, not setmode
* lib/binary-io.h, lib/cdefs.h, lib/fcntl.c, lib/regex.h:
* lib/stdint.in.h: Copy from Gnulib.