From 50c81b984a3e0ed59862949950df1af990e98d86 Mon Sep 17 00:00:00 2001
From: bapt <bapt@FreeBSD.org>
Date: Mon, 9 Sep 2019 15:28:22 +0000
Subject: [PATCH] m4: import patch from OpenBSD

by espie@
ifelse is special, fix argv parsing to avoid segfault

problem noticed by Matthew Green (netbsd), slightly different fix
so that argc counting makes more sense.

we might want to warn on wrong number of parameters later, but this is
somewhat inconsistent depending on the builtin right now.

okay millert@

Obtained from:	OpenBSD
---
 usr.bin/m4/eval.c | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/usr.bin/m4/eval.c b/usr.bin/m4/eval.c
index 1630b461f42..ee7ce2644be 100644
--- a/usr.bin/m4/eval.c
+++ b/usr.bin/m4/eval.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: eval.c,v 1.75 2017/06/15 13:48:42 bcallah Exp $	*/
+/*	$OpenBSD: eval.c,v 1.76 2017/10/23 15:21:19 espie Exp $	*/
 /*	$NetBSD: eval.c,v 1.7 1996/11/10 21:21:29 pk Exp $	*/
 
 /*-
@@ -201,8 +201,7 @@ expand_builtin(const char *argv[], int argc, int td)
 	}
 
 	case IFELTYPE:
-		if (argc > 4)
-			doifelse(argv, argc);
+		doifelse(argv, argc);
 		break;
 
 	case IFDFTYPE:
@@ -695,17 +694,17 @@ dotrace(const char *argv[], int argc, int on)
 static void
 doifelse(const char *argv[], int argc)
 {
-	cycle {
-		if (STREQ(argv[2], argv[3]))
+	while (argc > 4) {
+		if (STREQ(argv[2], argv[3])) {
 			pbstr(argv[4]);
-		else if (argc == 6)
+			break;
+		} else if (argc == 6) {
 			pbstr(argv[5]);
-		else if (argc > 6) {
+			break;
+		} else {
 			argv += 3;
 			argc -= 3;
-			continue;
 		}
-		break;
 	}
 }
 
-- 
2.45.0