5 POSIX specification:@* @url{https://pubs.opengroup.org/onlinepubs/9699919799/functions/mktime.html}
9 Portability problems fixed by Gnulib:
12 On native Windows platforms (mingw, MSVC), this function works incorrectly
13 when the environment variable @code{TZ} has been set by Cygwin.
15 @code{mktime} may go into an endless loop on some platforms.
17 @code{mktime} may occasionally return wrong results on some platforms.
20 Portability problems not fixed by Gnulib:
23 Native Windows platforms (mingw, MSVC) support only a subset of time
24 zones supported by GNU or specified by POSIX@. @xref{tzset}.