Move Leopard-specific type definitions to gdkquartz.h

Update includes subsequently where it matters.  Fixes build on Mac OS
X 10.4.

(cherry picked from commit e634f3fbe0498afc560530d9b92eb4709d7c7f97)

gdk/quartz/GdkQuartzView.c

@@ -23,6 +23,7 @@
 #include "gdkregion-generic.h"
 #include "gdkwindow-quartz.h"
 #include "gdkprivate-quartz.h"
+#include "gdkquartz.h"
 
 @implementation GdkQuartzView