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/gtk1/region.cpp

@@ -63,7 +63,7 @@ public:
         m_region = gdk_regions_union(wxGdkRegion(), refData.m_region);
     }
 
-    ~wxRegionRefData()
+    virtual ~wxRegionRefData()
     {
         if (m_region)
             gdk_region_destroy( m_region );