anchor.diff:  
   explain_error({unknown_protocol_for_system, System}) ->
     io_lib:format(
  -    "A process tried to communicate with system process ~p. Concuerror does not"
  -    " currently support communication with this process. Please contact the"
  +    "A process tried to send a message to system process ~p. Concuerror does"
  +    " not currently support communication with this process. Please contact the"
       " developers for more information.",[System]);
   explain_error({inconsistent_builtin,
                  [Module, Name, Arity, Args, OldResult, NewResult, Location]}) ->
  
positive.code:       NewEvent = Event#event{special = {message, MessageEvent}},
        {true, Info#concuerror_info{next_event = NewEvent}}
    end;
  
  run_built_in(erlang, halt, _, _, Info) ->
    #concuerror_info{next_event = Event} = Info,
  
negative.code:   {true, NewInfo#concuerror_info{extra = Tid}};
  
  run_built_in(Module, Name, Arity, Args, Info)
    when
      {Module, Name, Arity} =:= {erlang, put, 2} ->
    consistent_replay(Module, Name, Arity, Args, Info);
  
  %% For other built-ins check whether replaying has the same result:
  