+ A departure from SMF-based forums: redirectexit() will no longer ad…

…d the session variable to the URL if it's already in a cookie. I'll be honest with you, I never noticed that variable before, but it's started showing up everywhere in my new server. If you know why, feel free to share! Other than that, this update is very logical, so for those like me who have the problem, there you go. (Subs.php)

core/app/Subs.php

@@ -1125,8 +1125,8 @@ function redirectexit($setLocation = '', $refresh = false, $permanent = false)
 	if ($is_internal = !preg_match('~^(?:http|ftp)s?://~', $setLocation))
 		$setLocation = SCRIPT . ($setLocation != '' ? '?' . $setLocation : '');
 
-	// Put the session ID in.
-	if (defined('SID') && SID != '')
+	// Put the session ID in, if it's not already in a cookie.
+	if (defined('SID') && SID != '' && (!isset($_COOKIE[session_name()]) || $_COOKIE[session_name()] !== session_id()))
 		$setLocation = preg_replace('/^' . preg_quote(SCRIPT, '/') . '(?!\?' . preg_quote(SID, '/') . ')\\??/', SCRIPT . '?' . SID . ';', $setLocation);
 	// Keep that debug in their for template debugging!
 	elseif (isset($_GET['debug']))