[gtk+/gtk-3-22] wayland: Don't provide gsetting if dconf is not available

[Matthias Clasen <matthiasc src gnome org>]

commit 2b6f3f7867d297e44c35688e0407cfa6c91cc222
Author: Alex Ivanov <gnidorah ya ru>
Date:   Wed Nov 15 13:08:00 2017 +0000

    wayland: Don't provide gsetting if dconf is not available
    
    This makes gtk+ fall back to reading ~/.config/gtk-3.0/settings.ini
    on systems with Wayland, but without dconf (do those exist?).
    
    https://bugzilla.gnome.org/show_bug.cgi?id=790201

 gdk/wayland/gdkscreen-wayland.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/gdk/wayland/gdkscreen-wayland.c b/gdk/wayland/gdkscreen-wayland.c
index 9af09d4..125b4fa 100644
--- a/gdk/wayland/gdkscreen-wayland.c
+++ b/gdk/wayland/gdkscreen-wayland.c
@@ -657,6 +657,9 @@ gdk_wayland_screen_get_setting (GdkScreen   *screen,
 
   g_return_val_if_fail (GDK_IS_SCREEN (screen), FALSE);
 
+  if (g_settings_schema_source_get_default () == NULL)
+    return FALSE;
+
   entry = find_translation_entry_by_setting (name);
   if (entry != NULL)
     {