/*
* Note optimization in _renewthread:
* *lp must be pending when _renewthread called; if *l has been looked
* at already, the optimization is a bug.
*/
extern Relist*
_renewthread(Relist *lp, /* _relist to add to */
Reinst *ip, /* instruction to add */
Resublist *sep) /* pointers to subexpressions */
{
Relist *p;