tzset
=====

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

Gnulib module: tzset

Portability problems fixed by Gnulib:

  * On native Windows platforms (mingw, MSVC), this function works incorrectly when the environment variable TZ has been set by Cygwin.

Portability problems not fixed by Gnulib:

  * Native Windows platforms (mingw, MSVC) support only a subset of POSIX-specified values for the TZ environment variable, consisting of a time zone abbreviation containing exactly three ASCII letters with no daylight saving time or angle brackets, and with no support for tz database settings like TZ='America/New_York'.  Even this subset does not work on applications built via the Universal Windows Platform, as it does not make environment variables like TZ available to applications.

  * Older POSIX platforms do not support angle brackets in TZ values, as this feature was added in IEEE Std 1003.1-2001.