/* Return the UTC offset in seconds west of UTC, or 0 if it cannot be determined.  */
static int TimeZone(time_t t)
/* Return the UTC offset in seconds west of UTC, or 0 if it cannot be determined.  */
static int TimeZone(time_t t)
{
	struct tm *tm = gmtime(&t);
	struct tm  tm_utc;
	if (tm == NULL)
		return 0;
	tm_utc = *tm;
	tm = localtime(&t);
	if (tm == NULL)
		return 0;
	return tm_diff(&tm_utc, tm);
}