implement usage of __DIR__ to fix references on include

language.php

@@ -14,7 +14,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-require_once("config.php");
+require_once(__DIR__ . "/config.php");
 $lang = $config["defaultLanguage"];
 
 if (isset($_GET['lang'])) {
@@ -25,7 +25,7 @@ if (!file_exists($lang_file)) {
     error_log("Translation for " . $lang . " not found. Fallback to 'de-de'");
     $lang = "de-de";
 }
-$lang_file = dirname(__FILE__) . "/lang/lang." . $lang . ".php";
+$lang_file = __DIR__ . "/lang/lang." . $lang . ".php";
 require_once($lang_file);
 unset($lang_file);
 ?>