Merge from Gnulib

Merge from Gnulib

This incorporates:
2017-11-23 stat: work around Solaris bug with tv_nsec < 0
2017-11-12 maint: shorten https://lists.gnu.org/archive/html/... links
* build-aux/config.sub, doc/misc/texinfo.tex, lib/allocator.h:
* lib/fstatat.c, lib/intprops.h, lib/lstat.c, lib/signal.in.h:
* lib/stat-time.h, lib/stdio-impl.h, lib/stdio.in.h:
* lib/timespec.h, m4/alloca.m4, m4/extern-inline.m4:
* m4/faccessat.m4, m4/fstatat.m4, m4/gnulib-common.m4:
* m4/lstat.m4, m4/std-gnu11.m4, m4/sys_types_h.m4:
* m4/vararrays.m4:
Copy from Gnulib.