package/cpio: fix build with GCC 15

On systems running GCC 15, host-cpio will fail to build with errors like

  copyout.c:646:12: error: too many arguments to function 'xstat'; expected 0, have 2

and

  main.c:407:13: error: assignment to 'int (*)(void)' from incompatible pointer type 'int (*)(const char * restrict,  struct stat * restrict)' [-Wincompatible-pointer-types]

This was reported[1] and fixed upstream, but there is no new release
yet. Import the upstream patch for now.

Fixes:
https://autobuild.buildroot.org/results/a10c5f2b0f9cb05b2550fe97f1133deaaac97277/
(and many more)

[1] https://lists.gnu.org/archive/html/bug-cpio/2025-05/msg00000.html

Signed-off-by: Florian Larysch <fl@n621.de>
[Julien:
 - add missing "Signed-off-by:" in patch to fix check-package error
 - change "Upstream:" link to use the commitdiff in patch
 - add "Fixes:" in commit log
]
Signed-off-by: Julien Olivain <ju.o@free.fr>

package/cpio/0001-Fix-c23-conformity.patch

@@ -0,0 +1,48 @@
+From f42137f5ab9cf07d1e62edc05e0212688d3ebaa2 Mon Sep 17 00:00:00 2001
+From: Sergey Poznyakoff <gray@gnu.org>
+Date: Tue, 6 May 2025 21:02:43 +0300
+Subject: [PATCH] Fix c23 conformity
+
+Upstream: https://git.savannah.gnu.org/gitweb/?p=cpio.git;a=commitdiff;h=f42137f5ab9cf07d1e62edc05e0212688d3ebaa2
+Signed-off-by: Sergey Poznyakoff <gray@gnu.org>
+Signed-off-by: Florian Larysch <fl@n621.de>
+---
+ src/extern.h | 4 ++--
+ src/global.c | 4 ++--
+ 2 files changed, 4 insertions(+), 4 deletions(-)
+
+diff --git a/src/extern.h b/src/extern.h
+index bf3d5b3..455119b 100644
+--- a/src/extern.h
++++ b/src/extern.h
+@@ -96,8 +96,8 @@ extern char input_is_special;
+ extern char output_is_special;
+ extern char input_is_seekable;
+ extern char output_is_seekable;
+-extern int (*xstat) ();
+-extern void (*copy_function) ();
++extern int (*xstat) (const char *, struct stat *);
++extern void (*copy_function) (void);
+ extern char *change_directory_option;
+ 
+ #define STRINGIFY_BIGINT(i, b) umaxtostr (i, b)
+diff --git a/src/global.c b/src/global.c
+index 66686f2..5c6ab16 100644
+--- a/src/global.c
++++ b/src/global.c
+@@ -184,10 +184,10 @@ bool to_stdout_option = false;
+ 
+ /* A pointer to either lstat or stat, depending on whether
+    dereferencing of symlinks is done for input files.  */
+-int (*xstat) ();
++int (*xstat) (const char *, struct stat *);
+ 
+ /* Which copy operation to perform. (-i, -o, -p) */
+-void (*copy_function) () = 0;
++void (*copy_function) (void) = 0;
+ 
+ char *change_directory_option;
+ 
+-- 
+2.49.0
+