dt_node_promote
dt_node_promote(dnp->dn_left, dnp->dn_right, &dn);
dt_node_promote(lp, rp, dnp);
dt_node_promote(lp, rp, dnp);
dt_node_promote(lp, rp, dnp);
dt_node_promote(lp, rp, dnp);
dt_node_promote(lp, rp, dnp);
dt_node_promote(lp, rp, dnp);
dt_node_promote(lp, rp, dnp);
dt_node_promote(lp, rp, dnp);
dt_node_promote(lp, rp, dnp);
dt_node_promote(lp, rp, dnp);
dt_node_promote(lp, rp, dnp);
dt_node_promote(lp, rp, dnp);
dt_node_promote(lp, rp, dnp); /* see K&R[A7.11-13] */
dt_node_promote(lp, rp, dnp); /* see K&R[A7.6] */
dt_node_promote(lp, rp, dnp); /* see K&R[A7.6] */
extern void dt_node_promote(dt_node_t *, dt_node_t *, dt_node_t *);