leapyear
long leapyear;
leapyear = isleap(year);
value += __mon_lengths[leapyear][i] *
if (year < 1 && leapyear)
__mon_lengths[leapyear][rulep->r_mon - 1])
if (leapyear && rulep->r_day >= 60)
*janfirst += __secs_year_lengths[leapyear];
#define days_in_year(y) (leapyear(y) ? 366 : 365)
(month_days[(m) - 1] + (m == FEBRUARY ? leapyear(y) : 0))