From 8f9fc786328b91b2f7e913699e553616f60f35e5 Mon Sep 17 00:00:00 2001
From: Lars Brinkhoff <lars@nocrew.org>
Date: Wed, 20 Jun 2018 10:05:21 +0200
Subject: [PATCH] display: Fix X11 crash when DISPLAY unset.

---
 display/x11.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/display/x11.c b/display/x11.c
index 7d83c437..cb89deb6 100644
--- a/display/x11.c
+++ b/display/x11.c
@@ -272,6 +272,10 @@ ws_init(const char *crtname,    /* crt type name */
     xpixels = xp;               /* save screen size */
     ypixels = yp;
 
+    if (getenv ("DISPLAY") == NULL) {
+        return 0;
+    }
+
     XtToolkitInitialize();
     app_context = XtCreateApplicationContext();
     argc = 0;