[Buildroot] [PATCH] package/m4: fix build failure with gcc 15

[Joseph Zikusooka]

>From 08d03e3ac14325a05942a632c8cf7b2a7c06d880 Mon Sep 17 00:00:00 2001
From: "Joseph Zikusooka (ZIK)" <zik at jambula.net>
Date: Wed, 23 Apr 2025 15:53:56 +0300
Subject: [PATCH] package/m4: fix build failure with gcc 15

This is a temporary workaround to address build issues with host-m4
when using GCC 15, as encountered on
the recently released Fedora 42. The issue stems from stricter
compiler behavior introduced in recent
bersions of GCC.

A proper fix has already been committed upstream and will be included
in the next release of GNU m4:
https://git.savannah.gnu.org/cgit/m4.git/commit/?h=branch-1.4&id=a22c9802dd7e724eaefb21dc21d84ac2d3a49c89

Until that version is available in buildroot, this patch ensures
continued compatibility and successful
builds.

More context:
https://lists.buildroot.org/pipermail/buildroot/2025-April/776922.html

Signed-off-by: Joseph Zikusooka (ZIK) <zik at jambula.net>
---
 package/m4/m4.mk | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/package/m4/m4.mk b/package/m4/m4.mk
index 39ad898b10..ab8e194b06 100644
--- a/package/m4/m4.mk
+++ b/package/m4/m4.mk
@@ -10,4 +10,6 @@ M4_SITE = $(BR2_GNU_MIRROR)/m4
 M4_LICENSE = GPL-3.0+
 M4_LICENSE_FILES = COPYING

+HOST_M4_CONF_ENV = CFLAGS="$(HOST_CFLAGS) -std=gnu17"
+
 $(eval $(host-autotools-package))
-- 
2.49.0