added missing virtual dtors to base classes (patch 1150945)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@32347 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/gsocket.h

@@ -100,6 +100,8 @@ typedef void (*GSocketCallback)(GSocket *socket, GSocketEvent event,
 class GSocketGUIFunctionsTable
 {
 public:
+    // needed since this class declares virtual members
+    virtual ~GSocketGUIFunctionsTable() { }
     virtual bool OnInit() = 0;
     virtual void OnExit() = 0;
     virtual bool CanUseEventLoop() = 0;