Update from Gnulib

Update 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: