message: Add missing SetID method to fix Windows build
diff: @@ -430,6 +430,8 @@ protected:
  NativeProcessProtocol(lldb::pid_t pid, int terminal_fd,
  NativeDelegate &delegate);
  + void SetID(lldb::pid_t pid) { m_pid = pid; }
  +
  // interface for state handling
  void SetState(lldb::StateType state, bool notify_delegates = true);
  