SYS_gettid alternative on NetBSD

[Mayuresh <mayuresh%acm.org@localhost>]

When trying to build wip/py-torch on NetBSD 9.2 amd64, I get the following
errors:


    /usr/pkgsrc/work/wip/py-torch/work/pytorch/third_party/kineto/libkineto/src/ThreadUtil.cpp:52:32: error: 'SYS_gettid' was not declared in this scope
         _sysTid = (int32_t)syscall(SYS_gettid);

The concerned function is:

    int32_t systemThreadId() {
      if (!_sysTid) {
    #ifdef __APPLE__
        _sysTid = (int32_t)syscall(SYS_thread_selfid);
    #elif defined _MSC_VER
        _sysTid = (int32_t)GetCurrentThreadId();
    #else
        _sysTid = (int32_t)syscall(SYS_gettid);
    #endif
      }
      return _sysTid;
    }



One more error and concerned function is:

    /usr/pkgsrc/work/wip/py-torch/work/pytorch/third_party/kineto/libkineto/src/ThreadUtil.cpp: In function 'bool libkineto::setThreadName(const string&)':
    /usr/pkgsrc/work/wip/py-torch/work/pytorch/third_party/kineto/libkineto/src/ThreadUtil.cpp:105:62: error: too few arguments to function 'int pthread_setname_np(pthread_t, const char*, void*)'

    bool setThreadName(const std::string& name) {
    #ifdef __APPLE__
      return 0 == pthread_setname_np(name.c_str());
    #elif defined _MSC_VER
      // Per https://docs.microsoft.com/en-us/windows/win32/api/processthreadsapi/nf-processthreadsapi-setthreaddescription
      // Use runtime linking to set thread description
      static auto _SetThreadDescription = reinterpret_cast<decltype(&SetThreadDescription)>(getKernel32Func("SetThreadDescription"));
      if (!_SetThreadDescription) {
        return false;
      }
      std::wstring_convert<std::codecvt_utf8_utf16<wchar_t>> conv;
      std::wstring wname = conv.from_bytes(name);
      HRESULT hr = _SetThreadDescription(GetCurrentThread(), wname.c_str());
      return SUCCEEDED(hr);
    #else
      return 0 == pthread_setname_np(pthread_self(), name.c_str());
    #endif
    }

Would appreciate suggestions for patches.

-- 
Mayuresh