[winpr,timezone] reset timezone with tzset

when iterating over timezones and reset to original call tzset again to
reflect that new old timezone setting

winpr/libwinpr/timezone/TimeZoneIanaAbbrevMap.c

@@ -91,6 +91,7 @@ static void append_timezone(const char* dir, const char* name)
 	else
 		unsetenv("TZ");
 	free(tz);
+	tzset();
 }
 
 static void handle_link(const char* base, const char* dir, const char* name);

winpr/libwinpr/timezone/timezone.c

@@ -899,6 +899,7 @@ DWORD EnumDynamicTimeZoneInformation(const DWORD dwIndex,
 	else
 		unsetenv("TZ");
 	free(tzcopy);
+	tzset();
 
 	if (local_time)
 		dynamic_time_zone_from_localtime(local_time, lpTimeZoneInformation);