added wxRTTI to XRC handlers (patch #752996 by David Falkinder)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@21078 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

contrib/include/wx/xrc/xmlres.h

@@ -302,6 +302,7 @@ private:
 
 class WXXMLDLLEXPORT wxXmlResourceHandler : public wxObject
 {
+DECLARE_ABSTRACT_CLASS(wxXmlResourceHandler)
 public:
     // Constructor.
     wxXmlResourceHandler();