use wxOVERRIDE

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@76220 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/html/helpfrm.h

@@ -118,7 +118,7 @@ public:
 
     // we don't want to prevent the app from closing just because a help window
     // remains opened
-    virtual bool ShouldPreventAppExit() const { return m_shouldPreventAppExit; }
+    virtual bool ShouldPreventAppExit() const wxOVERRIDE { return m_shouldPreventAppExit; }
 
 protected:
     void Init(wxHtmlHelpData* data = NULL);