make USER-OMP code compatible with pre-c++ 11 compilers again

 public:

  ThrData(int tid, class Timer *t);

  ~ThrData() { delete _timer; _timer = nullptr; };

  ~ThrData() { delete _timer; _timer = NULL; };

  void check_tid(int);    // thread id consistency check

  int get_tid() const { return _tid; }; // our thread id.

 // disabled default methods

 private:

  ThrData() : _tid(-1), _timer(nullptr) {};

  ThrData() : _tid(-1), _timer(NULL) {};

};

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