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);
@@ -645,7 +645,7 @@ glob3(pathbuf, pathend, pathend_last, pattern, restpattern, pglob, limit)
 	if (pglob->gl_flags & GLOB_ALTDIRFUNC)
 		readdirfunc = pglob->gl_readdir;
 	else
-		readdirfunc = readdir;
+		readdirfunc = (struct dirent *(*)(void *))readdir;
 	while ((dp = (*readdirfunc)(dirp))) {
 		u_char *sc;
 		Char *dc;