message: Update install_sources.md
diff: @@ -296,6 +296,13 @@ you would typically invoke the following command:
  $ <b>bazel build --config=opt //tensorflow/tools/pip_package:build_pip_package</b>
  </pre>
  +To build a pip package for TensorFlow with CPU-only support using Intel(R) MKL DNN,
  +invoke the following command:
  +
  +<pre>
  +$ <b>bazel build --config=mkl --config=opt //tensorflow/tools/pip_package:build_pip_package</b>
  +</pre>
  +
  To build a pip package for TensorFlow with GPU support,
  invoke the following command:
  