bpo-36779: time.tzname returns empty string on Windows if default cod… (GH-13073)

bpo-36779: time.tzname returns empty string on Windows if default cod… (GH-13073)

Calling setlocale(LC_CTYPE, "") on a system where GetACP() returns CP_UTF8 results in empty strings in _tzname[].

This causes time.tzname to be an empty string.
I have reported the bug to the UCRT team and will follow up, but it will take some time get a fix into production.

In the meantime one possible workaround is to temporarily change the locale by calling setlocale(LC_CTYPE, "C") before calling _tzset and restore the current locale after if the GetACP() == CP_UTF8 or CP_UTF7

@zooba

https://bugs.python.org/issue36779
(cherry picked from commit b4c7defe58695a6670a8fdeaef67a638bbb47e42)

Co-authored-by: Paul Monson <paulmon@users.noreply.github.com>