Use wxGTK_CONV instead of wxConvUTF8

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@43297 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/gtk/listbox.cpp

@@ -516,7 +516,7 @@ void wxListBox::GtkInsertItems(const wxArrayString& items,
         wxString label = items[i];
 
         GtkTreeEntry* entry = gtk_tree_entry_new();
-        gtk_tree_entry_set_label(entry, wxConvUTF8.cWX2MB(label));
+        gtk_tree_entry_set_label(entry, wxGTK_CONV(label));
         gtk_tree_entry_set_destroy_func(entry,
                 (GtkTreeEntryDestroy)gtk_tree_entry_destroy_cb,
                             this);