days_in_month
accum += days_in_month[t->tm_mon];
static const int days_in_month[12] = {
ct->day > days_in_month(year, ct->mon) ||
days += days_in_month(year, i);
for (i = 1; days >= days_in_month(year, i); i++)
days -= days_in_month(year, i);