int mday = tp->tm_mday;
int mon = tp->tm_mon;
int year_requested = tp->tm_year;
- int isdst = tp->tm_isdst;
+ /* Normalize the value. */
+ int isdst = ((tp->tm_isdst >> (8 * sizeof (tp->tm_isdst) - 1))
+ | (tp->tm_isdst != 0));
/* 1 if the previous probe was DST. */
int dst2;