Removed dependency on php intl extension

app.php

@@ -10,9 +10,11 @@ require 'DatabaseAuthenticator.php';
 
 $supported_locales = array('nl_NL');  // English is default, Dutch is optional
 
-if ($locale = locale_accept_from_http($_SERVER['HTTP_ACCEPT_LANGUAGE'])) {
+if (isset($_SERVER['HTTP_ACCEPT_LANGUAGE'])) {
+    $locale = explode(',', $_SERVER['HTTP_ACCEPT_LANGUAGE'])[0];
+
     // nl -> nl_NL
-    if (locale_get_region($locale) == '')
+    if (preg_match('/^[a-z]{2}$/', $locale))
         $locale .= '_' . strtoupper($locale);
 
     if (in_array($locale, $supported_locales)) {