window: GtkPlug is conditionally supported on X11 only

We cannot do a type check on it if we don't have the X11 backend
compiled in.

https://bugzilla.gnome.org/show_bug.cgi?id=739885

diff --git a/gtk/gtkwindow.c b/gtk/gtkwindow.c
index 0d0fb888979e6bddb905ddc5496f946370b87c65..6cb355b56a22444143b7bc05dbaea88514abce52 100644 (file)
--- a/gtk/gtkwindow.c
+++ b/gtk/gtkwindow.c
@@ -1610,10 +1610,17 @@ gtk_window_constructed (GObject *object)
 {
   GtkWindow *window = GTK_WINDOW (object);
   GtkWindowPrivate *priv = window->priv;
+  gboolean is_plug;
 
   G_OBJECT_CLASS (gtk_window_parent_class)->constructed (object);
 
-  if (priv->type == GTK_WINDOW_TOPLEVEL && !GTK_IS_PLUG (window))
+#ifdef GDK_WINDOWING_X11
+  is_plug = GTK_IS_PLUG (window);
+#else
+  is_plug = FALSE;
+#endif
+
+  if (priv->type == GTK_WINDOW_TOPLEVEL && !is_plug)
     {
       priv->multipress_gesture = gtk_gesture_multi_press_new (GTK_WIDGET (object));
       gtk_gesture_single_set_button (GTK_GESTURE_SINGLE (priv->multipress_gesture), 0);