replaced with an alternative API in `tf.contrib.seq2seq`.

*   Intel MKL Integration
    (https://software.intel.com/en-us/articles/tensorflow-optimizations-on-modern-intel-architecture).
    Intel developed a number of optimized deep learning primitives: In addition
    to matrix multiplication and convolution, these building blocks include:

  elif is_windows():
    default_cc_opt_flags = '/arch:AVX'
  else:
    # On all other platforms, no longer use `-march=native` as this can result
    # in instructions that are too modern being generated. Users that want
    # maximum performance should compile TF in their environment and can pass
    # `-march=native` there.
    # See https://github.com/tensorflow/tensorflow/issues/45744 and duplicates