#include "wx/gdicmn.h"
#include "wx/math.h"
-class WXDLLIMPEXP_BASE wxDataInputStream;
-class WXDLLIMPEXP_BASE wxDataOutputStream;
+class WXDLLIMPEXP_FWD_BASE wxDataInputStream;
+class WXDLLIMPEXP_FWD_BASE wxDataOutputStream;
// clipping from Cohen-Sutherland