This patch fixes the errors that occur sif the DISPLAY environment
variable exists, but is an empty string.

patch by Bas Zoetekouw <bas@debian.org>

diff -Naur aumix-2.8.orig/src/common.c aumix-2.8/src/common.c
--- aumix-2.8.orig/src/common.c	2002-10-29 22:27:51.000000000 +0100
+++ aumix-2.8/src/common.c	2002-11-29 18:57:09.000000000 +0100
@@ -200,7 +200,8 @@
 */
 	if (interactive == IN_ANY) {
 #if defined (HAVE_GTK) || defined (HAVE_GTK1)
-		if (getenv("DISPLAY") != NULL)
+	    	char *d;
+		if ((d = getenv("DISPLAY")) && (*d != '\0'))
 			interactive = IN_GTK;
 #endif				/* HAVE_GTK || HAVE_GTK1 */
 #ifdef HAVE_CURSES