Don't export wxDataViewCtrlInternal unnecessarily.

wxDataViewCtrlInternal is a private class used only inside wxWidgets itself
and doesn't need to be exported from the shared library, so remove the
unnecessary WXDLLIMPEXP_ADV from its declaration.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@65214 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/gtk/dataview.cpp

@@ -103,7 +103,7 @@ private:
 WX_DECLARE_LIST(wxDataViewItem, ItemList);
 WX_DEFINE_LIST(ItemList)
 
-class WXDLLIMPEXP_ADV wxDataViewCtrlInternal
+class wxDataViewCtrlInternal
 {
 public:
     wxDataViewCtrlInternal( wxDataViewCtrl *owner, wxDataViewModel *wx_model, GtkWxTreeModel *gtk_model );