+int arch_valid(const char *, enum mandoc_os);
+void deroff(char **, const struct roff_node *);
+struct roff_node *roff_node_child(struct roff_node *);
+struct roff_node *roff_node_next(struct roff_node *);
+struct roff_node *roff_node_prev(struct roff_node *);
+int roff_node_transparent(struct roff_node *);
+int roff_tok_transparent(enum roff_tok);