Alternative clang on Windows link fix

Remove WXDLLIMPEXP_BASE from wxObjectEventFunctor declaration: this
class only has inline methods and so doesn't define any functions that
would need to be exported from the DLL.

This reverts commit c0f2f38011.

include/wx/event.h

@@ -210,11 +210,9 @@ private:
 };
 
 // A plain method functor for the untyped legacy event types:
-class WXDLLIMPEXP_BASE wxObjectEventFunctor : public wxEventFunctor
+class wxObjectEventFunctor : public wxEventFunctor
 {
 public:
-    virtual ~wxObjectEventFunctor();
-
     wxObjectEventFunctor(wxObjectEventFunction method, wxEvtHandler *handler)
         : m_handler( handler ), m_method( method )
         { }