[clutter/windows-fixes: 4/4] tests/conform: Don't set x11 backend unconditionally

[Chun-wei Fan <fanchunwei src gnome org>]

commit ff463f8692eb33c5b8a1287e120ea2a966241731
Author: Chun-wei Fan <fanchunwei src gnome org>
Date:   Wed Oct 20 14:56:36 2021 +0800

    tests/conform: Don't set x11 backend unconditionally
    
    We may not be running the tests on an X11-based system

 tests/conform/meson.build | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)
---
diff --git a/tests/conform/meson.build b/tests/conform/meson.build
index a8da1b398..25c03c794 100644
--- a/tests/conform/meson.build
+++ b/tests/conform/meson.build
@@ -6,11 +6,14 @@ test_cflags = [
 test_env = [
   'G_ENABLE_DIAGNOSTIC=0',
   'CLUTTER_ENABLE_DIAGNOSTIC=0',
-  'CLUTTER_BACKEND=x11',
   'G_TEST_SRCDIR=@0@'.format(meson.current_source_dir()),
   'G_TEST_BUILDDIR=@0@'.format(meson.current_build_dir()),
 ]
 
+if enabled_backends.contains('x11')
+  test_env += 'CLUTTER_BACKEND=x11'
+endif
+
 actor_tests = [
   'actor-anchors',
   'actor-destroy',