VISITED
if (j->live == VISITED)
if (i->live == VISITED)
i->live = VISITED;
if (up->p_state == VISITED) /* we already been here */
up->p_state = VISITED;
if (up->p_state == VISITED)
up->p_state = VISITED;
if (y->generation & VISITED)
#define MUX_VISIT(X) ((X)->mn_flags |= VISITED)
#define MUX_CLEAR(X) ((X)->mn_flags &= (~VISITED)); \
#define MUX_DIDVISIT(X) ((X)->mn_flags & VISITED)