before:
Etk_Widget *
etk_dialog_button_add(dialog, label, response_id)
        Etk_Widget *    dialog
        char *  label
        int     response_id


after:
Etk_Widget *
etk_dialog_button_add(dialog, label, response_id)
        Etk_Widget *    dialog
        char *  label
        int     response_id
        CODE:
        etk_dialog_button_add(ETK_DIALOG(dialog), label, response_id)