message: devices: inform user that tensorflow wasn't compiled with CUDA support
  The current behaviour can be confusing when no GPU are found on a
  computer that does have GPUs, so add a warning.
diff: @@ -47,9 +47,13 @@ int GetNumAvailableGPUs() {
  }
  }
  }
  -#endif // GOOGLE_CUDA
  LOG(INFO) << "Number of eligible GPUs (core count >= 8): "
  << num_eligible_gpus;
  +#else
  + LOG(INFO) << "Number of eligible GPUs (core count >= 8): "
  + << num_eligible_gpus
  + << " (Note: TensorFlow was not compiled with CUDA support)";
  +#endif // GOOGLE_CUDA
  return num_eligible_gpus;
  }
  