DORETURN
fpid = dofork(pp, DORETURN);
if ((s = dofork(pp, DORETURN)) == 0) { /* child */
case DORETURN:
if ((prchild = dofork(pp, DORETURN)) == 0) { /* child */
if ((child = dofork(pp, DORETURN)) == 0) { /* child */