Fix missing $extraDirs when open_basedir returns

Author: arsonik

src/Symfony/Component/Process/ExecutableFinder.php

@@ -51,7 +51,10 @@ public function addSuffix($suffix)
     public function find($name, $default = null, array $extraDirs = [])
     {
         if (ini_get('open_basedir')) {
-            $searchPath = explode(PATH_SEPARATOR, ini_get('open_basedir'));
+            $searchPath = array_merge(
+                explode(PATH_SEPARATOR, ini_get('open_basedir')),
+                $extraDirs
+            );
             $dirs = [];
             foreach ($searchPath as $path) {
                 // Silencing against https://bugs.php.net/69240