extern void config_add(splay_tree_t *config_tree, config_t *config);
extern config_t *lookup_config(splay_tree_t *config_tree, const char *variable);
extern config_t *lookup_config_next(splay_tree_t *config_tree, const config_t *config);
extern void config_add(splay_tree_t *config_tree, config_t *config);
extern config_t *lookup_config(splay_tree_t *config_tree, const char *variable);
extern config_t *lookup_config_next(splay_tree_t *config_tree, const config_t *config);