protected function loadRootDirConfig(array &$realConfig)
    {
        if (file_exists($this->getRootDir() . 'config.php')) {
            $config = null;

            // scope isolated require()
            $includeClosure = function ($configFile) use (&$config) {
                require($configFile);
            };
            if (PHP_VERSION_ID >= 50400) {
                $includeClosure = $includeClosure->bindTo(null);
            }

            $includeClosure($this->getRootDir() . 'config.php');

            if (is_array($config)) {
                if (isset($config['base_url'])) {
                    $config['base_url'] = rtrim($config['base_url'], '/') . '/';
                }
                if (isset($config['content_dir'])) {
                    $config['content_dir'] = rtrim($config['content_dir'], '/\\') . '/';
                }

                $realConfig = $config + $realConfig;
            }
        }
    }