prototype fixes (this time including pure virtual function detection)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@52771 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

interface/busyinfo.h

@@ -67,6 +67,6 @@ public:
     /**
         Hides and closes the window containing the information text.
     */
-    ~wxBusyInfo();
+    virtual ~wxBusyInfo();
 };