tz_change_interval
if (0 <= tz_change_interval && (tzloadflags & TZLOAD_FROMENV)
if (last_checked && now - last_checked < tz_change_interval)
if ((tz_change_interval <= 0 ? tz_change_interval < 0 : fresh_tzdata(now))
if (0 < tz_change_interval)
if (0 <= tz_change_interval || setname || !lcl_is_set)
if (0 <= tz_change_interval || !lcl_is_set)
if (0 <= tz_change_interval || !lcl_is_set)