Cleaner check to make sure inc/ files aren't accessed directly.

inc/mod/pages.php

@@ -4,10 +4,7 @@
  *  Copyright (c) 2010-2013 Tinyboard Development Group
  */
 
-if (realpath($_SERVER['SCRIPT_FILENAME']) == str_replace('\\', '/', __FILE__)) {
-	// You cannot request this file directly.
-	exit;
-}
+defined('TINYBOARD') or exit;
 
 function mod_page($title, $template, $args, $subtitle = false) {
 	global $config, $mod;