parse-datetime: don’t depend on tzname * lib/parse-datetime.y (TIME_ZONE_BUFSIZE): Move earlier. (parser_control) [!HAVE_STRUCT_TM_TM_ZONE]: New member tz_abbr, to save abbrs calculated by strftime %Z. (populate_local_time_zone_table): New function, which optimizes the HAVE_STRUCT_TM_TM_ZONE case as before, and falls back on strftime with %Z otherwise. Although strftime %Z can be more accurate than the old tzname based method, the new heuristic is still wrong so often that it probably doesn’t help all that much. (parse_datetime_body): Use it. * modules/parse-datetime (Depends-on): Remove tzname.