diff -Nrup a/timezone/zic.c b/timezone/zic.c
--- a/timezone/zic.c	2013-07-19 07:25:11.726506479 -0600
+++ b/timezone/zic.c	2013-07-19 07:27:15.059083404 -0600
@@ -2473,14 +2473,12 @@ oadd(t1, t2)
 const long	t1;
 const long	t2;
 {
-	register long	t;
-
-	t = t1 + t2;
-	if ((t2 > 0 && t <= t1) || (t2 < 0 && t >= t1)) {
+	if (t1 < 0 ? t2 < LONG_MIN - t1 : LONG_MAX - t1 < t2) {
 		error(_("time overflow"));
 		exit(EXIT_FAILURE);
 	}
-	return t;
+
+	return t1 + t2;
 }
 
 static zic_t