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/wfstream.h

@@ -34,7 +34,7 @@ public:
     wxFileInputStream(const wxString& ifileName);
     wxFileInputStream(wxFile& file);
     wxFileInputStream(int fd);
-    ~wxFileInputStream();
+    virtual ~wxFileInputStream();
 
     wxFileOffset GetLength() const;
 
@@ -133,7 +133,7 @@ public:
     wxFFileInputStream(const wxString& fileName, const wxChar *mode = _T("rb"));
     wxFFileInputStream(wxFFile& file);
     wxFFileInputStream(FILE *file);
-    ~wxFFileInputStream();
+    virtual ~wxFFileInputStream();
 
     wxFileOffset GetLength() const;