message: remove SIGALRM restriction
diff: @@ -443,9 +443,9 @@ static PHP_METHOD(swoole_process, signal)
  if (SwooleGS->start && (swIsWorker() || swIsMaster() || swIsManager() || swIsTaskWorker()))
  {
  - if (signo == SIGTERM || signo == SIGALRM)
  + if (signo == SIGTERM)
  {
  - swoole_php_fatal_error(E_WARNING, "cannot use swoole_process::signal in swoole_server.");
  + swoole_php_fatal_error(E_WARNING, "unable to register SIGTERM in swoole_server.");
  RETURN_FALSE;
  }
  }
  