Index: contrib/tzcode/stdtime/localtime.c
===================================================================
--- contrib/tzcode/stdtime/localtime.c
+++ contrib/tzcode/stdtime/localtime.c
@@ -1521,7 +1521,7 @@
 struct tm *
 gmtime(const time_t *const timep)
 {
-	struct tm *p_tm;
+	struct tm *p_tm, *res;
 
 	if (__isthreaded != 0) {
 		_pthread_once(&gmtime_once, gmtime_key_init);
@@ -1540,12 +1540,12 @@
 			}
 			_pthread_setspecific(gmtime_key, p_tm);
 		}
-		gmtsub(timep, 0L, p_tm);
-		return(p_tm);
+		res = gmtsub(timep, 0L, p_tm);
+		return (res);
 	}
 	else {
-		gmtsub(timep, 0L, &tm);
-		return(&tm);
+		res = gmtsub(timep, 0L, &tm);
+		return (res);
 	}
 }
 
@@ -1638,13 +1638,17 @@
 
 		tdelta = tdays / DAYSPERLYEAR;
 		idelta = tdelta;
-		if (tdelta - idelta >= 1 || idelta - tdelta >= 1)
+		if (tdelta - idelta >= 1 || idelta - tdelta >= 1) {
+			errno = EOVERFLOW;
 			return NULL;
+		}
 		if (idelta == 0)
 			idelta = (tdays < 0) ? -1 : 1;
 		newy = y;
-		if (increment_overflow(&newy, idelta))
+		if (increment_overflow(&newy, idelta)) {
+			errno = EOVERFLOW;
 			return NULL;
+		}
 		leapdays = leaps_thru_end_of(newy - 1) -
 			leaps_thru_end_of(y - 1);
 		tdays -= ((time_t) newy - y) * DAYSPERNYEAR;
@@ -1672,18 +1676,24 @@
 		++idays;
 	}
 	while (idays < 0) {
-		if (increment_overflow(&y, -1))
+		if (increment_overflow(&y, -1)) {
+			errno = EOVERFLOW;
 			return NULL;
+		}
 		idays += year_lengths[isleap(y)];
 	}
 	while (idays >= year_lengths[isleap(y)]) {
 		idays -= year_lengths[isleap(y)];
-		if (increment_overflow(&y, 1))
+		if (increment_overflow(&y, 1)) {
+			errno = EOVERFLOW;
 			return NULL;
+		}
 	}
 	tmp->tm_year = y;
-	if (increment_overflow(&tmp->tm_year, -TM_YEAR_BASE))
+	if (increment_overflow(&tmp->tm_year, -TM_YEAR_BASE)) {
+		errno = EOVERFLOW;
 		return NULL;
+	}
 	tmp->tm_yday = idays;
 	/*
 	** The "extra" mods below avoid overflow problems.