package/tmux: fix build failure due to type mismatch

Package tmux fails to build with:
compat/utf8proc.c: In function 'utf8proc_mbtowc':
compat/utf8proc.c:51:39: error: passing argument 3 of 'utf8proc_iterate' from incompatible pointer type [-Wincompatible-pointer-types]
   51 |         slen = utf8proc_iterate(s, n, pwc);
      |                                       ^~~
      |                                       |
      |                                       wchar_t * {aka long int *}

Add local patch already committed upstream to fix it.

Fixes:
https://autobuild.buildroot.net/results/651/6510cfb16d0c3f3772918cd3bde0542d0b59a230/

Signed-off-by: Giulio Benetti <giulio.benetti@benettiengineering.com>
Signed-off-by: Julien Olivain <ju.o@free.fr>
(cherry picked from commit 7cf46f0384)
Signed-off-by: Thomas Perale <thomas.perale@mind.be>

package/tmux/0001-Cast-to-avoid-warnings-on-32-bit-architectures.-GitH.patch

@@ -0,0 +1,28 @@
+From f812b8d30456c071ee23e9a02d6ce16036fd3f68 Mon Sep 17 00:00:00 2001
+From: Nicholas Marriott <nicholas.marriott@gmail.com>
+Date: Wed, 29 Oct 2025 08:47:45 +0000
+Subject: [PATCH] Cast to avoid warnings on 32-bit architectures. GitHub issue
+ 4597.
+
+Upstream: https://github.com/tmux/tmux/commit/f812b8d30456c071ee23e9a02d6ce16036fd3f68
+Signed-off-by: Giulio Benetti <giulio.benetti@benettiengineering.com>
+---
+ compat/utf8proc.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/compat/utf8proc.c b/compat/utf8proc.c
+index dd4ab27f..147da696 100644
+--- a/compat/utf8proc.c
++++ b/compat/utf8proc.c
+@@ -48,7 +48,7 @@ utf8proc_mbtowc(wchar_t *pwc, const char *s, size_t n)
+ 	 * *pwc == -1 indicates invalid codepoint
+ 	 * slen < 0 indicates an error
+ 	 */
+-	slen = utf8proc_iterate(s, n, pwc);
++	slen = utf8proc_iterate(s, n, (utf8proc_int32_t*)pwc);
+ 	if (*pwc == (wchar_t)-1 || slen < 0)
+ 		return (-1);
+ 	return (slen);
+-- 
+2.47.3
+