[HttpFoundation] made X_REWRITE_URL only available on Windows platforms

src/Symfony/Component/HttpFoundation/Request.php

@@ -1057,7 +1057,7 @@ class Request
     {
         $requestUri = '';
 
-        if ($this->headers->has('X_REWRITE_URL')) {
+        if ($this->headers->has('X_REWRITE_URL') && false !== stripos(PHP_OS, 'WIN')) {
             // check this first so IIS will catch
             $requestUri = $this->headers->get('X_REWRITE_URL');
         } elseif ($this->server->get('IIS_WasUrlRewritten') == '1' && $this->server->get('UNENCODED_URL') != '') {