#include "wx/overlay.h"
-#if wxHAS_NATIVE_OVERLAY
+#ifdef wxHAS_NATIVE_OVERLAY
#if defined(__WXMAC__)
#include "wx/mac/carbon/private/overlay.h"
#include "wx/bitmap.h"
+class WXDLLIMPEXP_CORE wxWindow;
+
// generic implementation of wxOverlay
class wxOverlayImpl
{