rem: Wait(SIGBREAKF_CTRL_F);
add: Wait(1UL << signal);
context: ExpungeUnit ( struct AHIDevUnit *iounit,              struct AHIBase *AHIBase ){  struct Task *unittask;  unittask = (struct Task *) iounit->Process;  iounit->Process = (struct Process *) FindTask(NULL);  Signal(unittask,SIGBREAKF_CTRL_F);  Wait(SIGBREAKF_CTRL_F);  AHIBase->ahib_DevUnits[iounit->UnitNum]=NULL;  FreeVec(iounit->Voices);  FreeVec(iounit);}