[clutter] tests: Force X11 backend for the pixmap test

[Emmanuele Bassi <ebassi src gnome org>]

commit 7501f3b4f99260bc188cf5114168660d9124ae9d
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Fri Dec 11 15:51:30 2015 +0000

    tests: Force X11 backend for the pixmap test
    
    So it's usable as long as the X11 backend support is compiled into
    Clutter — and we can use this test to check that overriding works
    as intended.

 tests/interactive/test-pixmap.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)
---
diff --git a/tests/interactive/test-pixmap.c b/tests/interactive/test-pixmap.c
index 445cf5f..7593457 100644
--- a/tests/interactive/test-pixmap.c
+++ b/tests/interactive/test-pixmap.c
@@ -211,6 +211,10 @@ test_pixmap_main (int argc, char **argv)
   int                 i;
   int                  row_height;
 
+#ifdef CLUTTER_WINDOWING_X11
+  clutter_set_windowing_backend (CLUTTER_WINDOWING_X11);
+#endif
+
   if (clutter_init (&argc, &argv) != CLUTTER_INIT_SUCCESS)
     return 1;