links_entry
RB_ENTRY(links_entry) entry;
struct links_entry *fnext;
links_cmp(struct links_entry *e1, struct links_entry *e2)
RB_HEAD(ltree, links_entry) links = RB_INITIALIZER(&links);
RB_GENERATE_STATIC(ltree, links_entry, entry, links_cmp);
static struct links_entry *free_list = NULL;
struct links_entry ltmp, *le;
le = malloc(sizeof(struct links_entry));