Update from Gnulib

Update from Gnulib

This incorporates:
2019-11-24 Fix errors in C++ mode on mingw
2019-11-24 time_r: Fix for mingw (regression from 2019-11-16)
2019-11-24 sys_time: Fix errors in C++ mode on mingw
2019-11-22 intprops: INT_MULTIPLY_WRAPV speedup for GCC 8.4+
2019-11-21 Disable many _GL_CXXALIASWARN on non-glibc
2019-11-21 Fix various errors in _GL_CXXALIAS_SYS invocations
2019-11-19 intprops: INT_MULTIPLY_WRAPV speedup for GCC 9.3+
2019-11-18 stdint: Define [u]intptr_t correctly on 64-bit native Windows
2019-11-18 stdint: Fix value of WINT_MAX when we override wint_t
2019-11-18 stdint: Avoid "conflicting types" error on mingw 5.22
2019-11-16 time_r: Fix for mingw
2019-11-06 regex: now back in sync with glibc
* lib/intprops.h, lib/regexec.c, lib/signal.in.h:
* lib/stdint.in.h, lib/stdio.in.h, lib/stdlib.in.h:
* lib/string.in.h, lib/sys_select.in.h, lib/sys_time.in.h:
* lib/time.in.h, lib/unistd.in.h, m4/time_r.m4:
Copy from Gnulib.