[glib] Fix up appinfo test

[Matthias Clasen <matthiasc src gnome org>]

commit 5efc038e0dc77459ee5258b76640da423ded458e
Author: Matthias Clasen <mclasen redhat com>
Date:   Sat Nov 23 22:24:00 2013 -0500

    Fix up appinfo test
    
    Make it possible to skip the terminal-launching test simply
    by setting DISPLAY= . Previously, you had to unset DISPLAY,
    which is a little more cumbersome.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=711178

 gio/tests/appinfo.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/gio/tests/appinfo.c b/gio/tests/appinfo.c
index 5f84cbd..e04071a 100644
--- a/gio/tests/appinfo.c
+++ b/gio/tests/appinfo.c
@@ -15,7 +15,7 @@ test_launch (void)
   const gchar *path;
   gchar *uri;
 
-  if (!g_getenv ("DISPLAY"))
+  if (g_getenv ("DISPLAY") == NULL || g_getenv ("DISPLAY")[0] == '\0')
     {
       g_printerr ("No DISPLAY.  Skipping test.  ");
       return;