Import the time_r gnulib module

Import the time_r gnulib module

This allows GDB to use localtime_r unconditionally.

See https://lists.gnu.org/archive/html/bug-gnulib/2019-11/msg00022.html
for details on the compile error mentioned below.

gdb/ChangeLog:

2019-11-15  Christian Biesinger  <cbiesinger@google.com>

	* gdbsupport/common-defs.h: Include time.h before pathmax.h to
	avoid compile errors.

gnulib/ChangeLog:

2019-11-15  Christian Biesinger  <cbiesinger@google.com>

	* Makefile.in: Regenerate.
	* aclocal.m4: Regenerate.
	* config.in: Regenerate.
	* configure: Regenerate.
	* import/Makefile.am: Update.
	* import/Makefile.in: Regenerate.
	* import/m4/gnulib-cache.m4: Update.
	* import/m4/gnulib-comp.m4: Update.
	* import/m4/time_r.m4: New file.
	* import/time_r.c: New file.
	* update-gnulib.sh: Import time_r.

Change-Id: I53fc861b192940d613ca97f2910b4533c730f667