[openwrt/openwrt] tools: m4: update to 1.4.21

[LEDE Commits]

robimarko pushed a commit to openwrt/openwrt.git, branch main:
https://git.openwrt.org/ce9a0ff3fb88d037080aaf95af92ac5da4fcfdba

commit ce9a0ff3fb88d037080aaf95af92ac5da4fcfdba
Author: John Audia <therealgraysky at proton.me>
AuthorDate: Wed Feb 11 17:56:42 2026 -0500

    tools: m4: update to 1.4.21
    
    Changelog: https://github.com/autotools-mirror/m4/blob/branch-1.4/NEWS
    
    This update fixes a build error on my system:
    ./string.h:777:20: error: expected identifier or '(' before '_Generic'
      777 | _GL_EXTERN_C void *memchr (const void *__s, int __c, size_t __n)
          |                    ^~~~~~
    
    Signed-off-by: John Audia <therealgraysky at proton.me>
    Link: https://github.com/openwrt/openwrt/pull/21987
    Signed-off-by: Robert Marko <robimarko at gmail.com>
---
 tools/m4/Makefile | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/m4/Makefile b/tools/m4/Makefile
index eaa46ec4f8..84898904fe 100644
--- a/tools/m4/Makefile
+++ b/tools/m4/Makefile
@@ -8,11 +8,11 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=m4
 PKG_CPE_ID:=cpe:/a:gnu:m4
-PKG_VERSION:=1.4.20
+PKG_VERSION:=1.4.21
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz
 PKG_SOURCE_URL:=@GNU/$(PKG_NAME)
-PKG_HASH:=6ac4fc31ce440debe63987c2ebbf9d7b6634e67a7c3279257dc7361de8bdb3ef
+PKG_HASH:=38ae59f7a30bf9c108193cc5c25fbb06014f21e230c7ede2eff614f7b7c37ed8
 
 HOST_BUILD_PARALLEL:=1