message: Fix Mac OSX build linker error.
  ImportError: dlopen(/Volumes/BuildData/tmpfs/tmp/bazel/d1b2600cd78e76a92812a06683f5de10/execroot/org_tensorflow/bazel-out/host/bin/tensorflow/python/keras/api/create_tensorflow.python_api_1_keras_python_api_gen.runfiles/org_tensorflow/tensorflow/python/_pywrap_tensorflow_internal.so, 6): Symbol not found: __ZN10tensorflow14CSRMatMulCPUOpINSt3__17complexIdEEE10kMaxShardsE
diff: @@ -43,6 +43,20 @@ limitations under the License.
  namespace tensorflow {
  +// TODO(anudhyan): These constants may be tuned based on the performance of
  +// 'benchmark_sparse_matrix_mat_vec_mul'. We would like to find constants
  +// which work across hardware platforms for typical matrix sizes. It should be
  +// possible to observe at least 30-50% improvement as we increase the number
  +// of threads by 1. If not, then it may we worth increasing kMaxShards and
  +// kNumShardsPerThread. However, once we have too many shards, latency may be
  +// dominated by per-shard overhead.
  +//
  +// Maximum number of shards into which to divide the computation for each CSR
  +// Sparse Matrix instance.
  +static constexpr int32 kMaxShards = 20;
  +// Number of shards allocated to each thread.
  +static constexpr int32 kNumShardsPerThread = 3;
  +
  typedef Eigen::ThreadPoolDevice CPUDevice;
  typedef Eigen::GpuDevice GPUDevice;
  @@ -147,16 +161,6 @@ class CSRMatMulCPUOp : public CSRMatMulOp<CPUDevice, T> {
  using MatrixMap = Eigen::Map<Matrix>;
  public:
  - // TODO(anudhyan): These constants may be tuned based on the performance of
  - // 'benchmark_sparse_matrix_mat_vec_mul'. We would like to find constants
  - // which work across hardware platforms for typical matrix sizes. It should be
  - // possible to observe at least 30-50% improvement as we increase the number
  - // of threads by 1. If not, then it may we worth increasing kMaxShards and
  - // kNumShardsPerThread. However, once we have too many shards, latency may be
  - // dominated by per-shard overhead.
  - static constexpr int32 kMaxShards = 20;
  - static constexpr int32 kNumShardsPerThread = 3;
  -
  explicit CSRMatMulCPUOp(OpKernelConstruction* c)
  : CSRMatMulOp<CPUDevice, T>(c) {}
  