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/os2/helpwin.h

@@ -24,7 +24,7 @@ class WXDLLEXPORT wxWinHelpController: public wxHelpControllerBase
 
  public:
   wxWinHelpController();
-  ~wxWinHelpController();
+  virtual ~wxWinHelpController();
 
   // Must call this to set the filename and server name
   virtual bool Initialize(const wxString& file);