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/cocoa/sound.h

@@ -29,7 +29,7 @@ public:
     :   m_cocoaNSSound(NULL)
     {   LoadWAV(data,size,true); }
     wxSound(const wxSound& sound); // why not?
-    ~wxSound();
+    virtual ~wxSound();
 
 public:
     bool Create(const wxString& fileName, bool isResource = false);