Fix GCC 15 warnings

Author: fjtrujy

newlib/libc/posix/glob.c

@@ -620,7 +620,7 @@ glob3(pathbuf, pathend, pathend_last, pattern, restpattern, pglob, limit)
 	 * and dirent.h as taking pointers to differently typed opaque
 	 * structures.
 	 */
-	struct dirent *(*readdirfunc)();
+	struct dirent *(*readdirfunc)(void *);
 
 	if (pathend > pathend_last)
 		return (1);