Update from Gnulib

Update from Gnulib

This incorporates:
2019-01-26 getloadavg: Add support for Android
2019-01-24 fchownat: Fix compilation error on Android 4.3
2019-01-24 mbtowc: Fix compilation error on Android 4.3
2019-01-24 random: Fix compilation error on Android 4.3
2019-01-24 renameat: Fix compilation error on Android 4.3
2019-01-24 unlinkat: Fix compilation error on Android 4.3
2019-01-19 gettext: support disabling use of VLAs
2019-01-17 sys_stat: Fix warning on OS/2 kLIBC
2019-01-17 fcntl: Fix syntax error (regression from 2018-10-05)
2019-01-10 verify: Enable _GL_HAVE_STATIC_ASSERT for recent G++
2018-12-22 stdioext: port to newer 32-bit Android
2018-12-16 libc-config: Support HP-UX cc in C99 mode.
* build-aux/config.guess, build-aux/config.sub, doc/misc/texinfo.tex:
* lib/cdefs.h, lib/fcntl.c, lib/getloadavg.c, lib/gettext.h:
* lib/regexec.c, lib/stdio-impl.h, lib/stdio.in.h, lib/stdlib.in.h:
* lib/sys_stat.in.h, lib/unistd.in.h, lib/verify.h, m4/stdlib_h.m4:
Copy from Gnulib.
* lib/gnulib.mk.in: Regenerate.