extern void free_config(config_t *);
extern void config_add(avl_tree_t *, config_t *);
extern config_t *lookup_config(const avl_tree_t *, char *);
extern void free_config(config_t *);
extern void config_add(avl_tree_t *, config_t *);
extern config_t *lookup_config(const avl_tree_t *, char *);