message: Define EIGEN_USE_THREADS only if it is not defined yet
diff: @@ -16,7 +16,9 @@ limitations under the License.
  #ifndef TENSORFLOW_CORE_LIB_CORE_THREADPOOL_INTERFACE_H_
  #define TENSORFLOW_CORE_LIB_CORE_THREADPOOL_INTERFACE_H_
  +#ifndef EIGEN_USE_THREADS
  #define EIGEN_USE_THREADS
  +#endif
  #include "third_party/eigen3/unsupported/Eigen/CXX11/Tensor"
  