gmtime_r
========

POSIX specification:
 https://pubs.opengroup.org/onlinepubs/9699919799/functions/gmtime_r.html

Gnulib module: time_r

Portability problems fixed by Gnulib:

  * This function is missing on some platforms: mingw, MSVC 14.

  * This function is not declared unless _REENTRANT is defined, on some platforms: HP-UX 11.

Portability problems not fixed by Gnulib:

  * On some platforms, this function yields incorrect values for timestamps before the year 1: MacOS X 10.5, Solaris 11.3.