fix integer overflow of tm_year in __secs_to_tm

the overflow check for years+100 did not account for the extra
year computed from the remaining months. instead, perform this
check after obtaining the final number of years.

src/time/__secs_to_tm.c

@@ -60,15 +60,16 @@ int __secs_to_tm(long long t, struct tm *tm)
 	for (months=0; days_in_month[months] <= remdays; months++)
 		remdays -= days_in_month[months];
 
+	if (months >= 10) {
+		months -= 12;
+		years++;
+	}
+
 	if (years+100 > INT_MAX || years+100 < INT_MIN)
 		return -1;
 
 	tm->tm_year = years + 100;
 	tm->tm_mon = months + 2;
-	if (tm->tm_mon >= 12) {
-		tm->tm_mon -=12;
-		tm->tm_year++;
-	}
 	tm->tm_mday = remdays + 1;
 	tm->tm_wday = wday;
 	tm->tm_yday = yday;