mark all dtors which are virtual because base class dtor is virtual explicitly virtual themselves

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@41020 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/univ/menu.cpp

@@ -123,7 +123,7 @@ class wxPopupMenuWindow : public wxPopupTransientWindow
 public:
     wxPopupMenuWindow(wxWindow *parent, wxMenu *menu);
 
-    ~wxPopupMenuWindow();
+    virtual ~wxPopupMenuWindow();
 
     // override the base class version to select the first item initially
     virtual void Popup(wxWindow *focus = NULL);