tools: cpio: fix compilation with GCC15

Fedora 42 updated to GCC15 which now defaults to GNU23 as the default
instead of GNU17[1], and this breaks cpio compilation.

Its been reported upstream [2], so import the patch attached to the bug
report that fixes compilation with GCC15.

[1] https://gcc.gnu.org/gcc-15/porting_to.html#c23
[2] https://savannah.gnu.org/bugs/?66297

Link: https://github.com/openwrt/openwrt/pull/18506
Signed-off-by: Robert Marko <[email protected]>

tools/cpio/patches/cpio-c23.patch

@@ -0,0 +1,23 @@
+--- a/src/extern.h
++++ b/src/extern.h
+@@ -97,7 +97,8 @@ extern char input_is_special;
+ extern char output_is_special;
+ extern char input_is_seekable;
+ extern char output_is_seekable;
+-extern int (*xstat) ();
++//void not good enough
++extern int (*xstat) (const char * restrict,  struct stat * restrict);
+ extern void (*copy_function) ();
+ extern char *change_directory_option;
+ 
+--- a/src/global.c
++++ b/src/global.c
+@@ -185,7 +185,7 @@ 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 * restrict,  struct stat * restrict);
+ 
+ /* Which copy operation to perform. (-i, -o, -p) */
+ void (*copy_function) () = 0;