git: 1d94e2e0f2ee - main - m4: Const correctness for C23

The branch main has been updated by ivy:

URL: https://cgit.FreeBSD.org/src/commit/?id=1d94e2e0f2ee21d5a4596efc0570d06e3dea0a6e

commit 1d94e2e0f2ee21d5a4596efc0570d06e3dea0a6e
Author:     Lexi Winter <ivy@FreeBSD.org>
AuthorDate: 2026-08-03 14:09:03 +0000
Commit:     Lexi Winter <ivy@FreeBSD.org>
CommitDate: 2026-08-03 14:09:03 +0000

    m4: Const correctness for C23
    
    On some platforms, e.g. Linux Clang 22.1.8 / glibc 2.43, strchr()
    now implements the C23 behaviour where passing a const pointer to
    strchr() also returns a const pointer.  This breaks m4 during the
    bootstrap build, since it assumes the return value is always a
    mutable pointer.
    
    Since the returned value is never modified, simply make the
    temporary const.
    
    MFC after:      1 week
    Reviewed by:    bapt, dim
    Sponsored by:   The FreeBSD Foundation
    Differential Revision:  https://reviews.freebsd.org/D58494
---
 usr.bin/m4/misc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/usr.bin/m4/misc.c b/usr.bin/m4/misc.c
index 24e91c572f4d..71d0734fa874 100644
--- a/usr.bin/m4/misc.c
+++ b/usr.bin/m4/misc.c
@@ -70,7 +70,7 @@ unsigned char *endpbb;			/* end of push-back buffer     */
 ptrdiff_t
 doindex(const char *s1, const char *s2)
 {
-	char *t;
+	const char *t;
 
 	t = strstr(s1, s2);
 	if (t == NULL)