From ee12faa062c04a49bf6fe4e6867bad8606e2413f Mon Sep 17 00:00:00 2001
From: Ed Maste <emaste@FreeBSD.org>
Date: Tue, 5 Sep 2023 12:35:31 -0400
Subject: [PATCH] bspatch: use C23 overflow checking math now that it is
 available

Reviewed by:	des
Sponsored by:	The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D41771
---
 usr.bin/bsdiff/bspatch/bspatch.c | 10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/usr.bin/bsdiff/bspatch/bspatch.c b/usr.bin/bsdiff/bspatch/bspatch.c
index a596ab1837dd..d7fabddabbfe 100644
--- a/usr.bin/bsdiff/bspatch/bspatch.c
+++ b/usr.bin/bsdiff/bspatch/bspatch.c
@@ -36,6 +36,7 @@
 #include <fcntl.h>
 #include <libgen.h>
 #include <limits.h>
+#include <stdckdint.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -64,15 +65,8 @@ add_off_t(off_t a, off_t b)
 {
 	off_t result;
 
-#if __GNUC__ >= 5 || \
-    (defined(__has_builtin) && __has_builtin(__builtin_add_overflow))
-	if (__builtin_add_overflow(a, b, &result))
+	if (ckd_add(&result, a, b))
 		errx(1, "Corrupt patch");
-#else
-	if ((b > 0 && a > OFF_MAX - b) || (b < 0 && a < OFF_MIN - b))
-		errx(1, "Corrupt patch");
-	result = a + b;
-#endif
 	return result;
 }