Use _tzset() on windows before localtime_s
@@ -1345,6 +1345,7 @@ JANET_CORE_FN(os_date,
if (argc >= 2 && janet_truthy(argv[1])) {
/* local time */
#ifdef JANET_WINDOWS
+ _tzset();
localtime_s(&t_infos, &t);
t_info = &t_infos;
#else
