--- a/daemon/gdm-server.c	2014-07-30 23:00:17.786841724 +0200
+++ b/daemon/gdm-server.c	2014-07-30 23:02:10.491239180 +0200
@@ -322,7 +322,11 @@
 fallback:
 #endif
 
-        server->priv->command = g_strdup_printf (X_SERVER X_SERVER_ARG_FORMAT, verbosity, debug_options);
+        if (g_getenv("GDM_X_SERVER") != NULL) {
+            server->priv->command = g_strdup (g_getenv("GDM_X_SERVER"));
+        } else {
+            server->priv->command = g_strdup_printf (X_SERVER X_SERVER_ARG_FORMAT, verbosity, debug_options);
+        }
 }
 
 static gboolean