#include "unify.h"
int Destroy_Event(int event_id);
Destroy_Event(3) frees the resources associated with the
event counter associated with event_id.
Destroy_Event(3) returns the event_id if
successful. Otherwise, a value of -1 is returned.
It is not clear what happens if Destroy_Event(3) is
called while several processes are blocked on the same event with Await(3).