codice:
function array_sort(&$arr, $callback = null){
	if($callback === null)
		sort($arr);
	else{
		for($i = 1, $j = count($arr), $k = null; $i < $j; $i++){
			$result = call_user_func($callback, $arr[$i], $arr[$i - 1]);
			if($result === -1){
				$k = $i + $result;
				$item = $arr[$i];
				$arr[$i] = $arr[$k];
				$arr[$k] = $item;
			}
		}
		if($k !== null)
			array_sort($arr, $callback);
	}
}

function sortFileByDate($f1, $f2){
	return	filemtime($f1) < filemtime($f2) ? 1 : -1;
}

$fileList = glob('*.*');
array_sort($fileList, 'sortFileByDate');
echo '<pre>';
var_dump($fileList);
exit('</pre>');