typedef void *user_data_create_func (void *aux1, void *aux2);
-struct categoricals *categoricals_create (const struct interaction **, size_t n_int,
+struct categoricals *categoricals_create (struct interaction *const *, size_t n_int,
const struct variable *wv, enum mv_class exclude,
user_data_create_func *udf,
update_func *update, void *aux1, void *aux2);