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

include/wx/html/helpdlg.h

@@ -44,7 +44,7 @@ public:
     wxHtmlHelpDialog(wxWindow* parent, wxWindowID wxWindowID,
                     const wxString& title = wxEmptyString,
                     int style = wxHF_DEFAULT_STYLE, wxHtmlHelpData* data = NULL);
-    ~wxHtmlHelpDialog();
+    virtual ~wxHtmlHelpDialog();
 
     bool Create(wxWindow* parent, wxWindowID id, const wxString& title = wxEmptyString,
                 int style = wxHF_DEFAULT_STYLE);