$NetBSD: patch-af,v 1.1 2008/05/22 12:30:44 tron Exp $

--- src/main.c.orig	2001-08-17 05:47:41.000000000 +0100
+++ src/main.c	2008-05-22 13:20:38.000000000 +0100
@@ -1444,8 +1444,10 @@
 /*
  * Open display, get options/resources and create the window
  */
-    if ((display_name = getenv("DISPLAY")) == NULL)
-	display_name = ":0";
+    if ((display_name = getenv("DISPLAY")) == NULL) {
+	print_error("display not defined");
+	exit(EXIT_FAILURE);
+    }
 
     get_options(argc, argv);