[gtk+] Make display test not fail under Wayland

[Matthias Clasen <matthiasc src gnome org>]

commit cbe5e596af4f7b8659c2f392fd77bd048720e5b8
Author: Matthias Clasen <mclasen redhat com>
Date:   Fri Aug 28 12:26:25 2015 -0400

    Make display test not fail under Wayland
    
    This test really only works under X, since it relies on modifying
    the DISPLAY env var.

 testsuite/gdk/display.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/testsuite/gdk/display.c b/testsuite/gdk/display.c
index 6ca7818..297c8e8 100644
--- a/testsuite/gdk/display.c
+++ b/testsuite/gdk/display.c
@@ -19,6 +19,7 @@ static void
 test_unset_display_subprocess2 (void)
 {
   g_unsetenv ("DISPLAY");
+
   gdk_init (NULL, NULL);
 }
 
@@ -69,6 +70,8 @@ main (int argc, char *argv[])
 {
   g_test_init (&argc, &argv, NULL);
 
+  gdk_set_allowed_backends ("x11");
+
   g_test_add_func ("/display/unset-display", test_unset_display);
   g_test_add_func ("/display/unset-display/subprocess/1", test_unset_display_subprocess1);
   g_test_add_func ("/display/unset-display/subprocess/2", test_unset_display_subprocess2);