Merge pull request #3099 from tensorflow/MarkDaoust-patch-2

Update compile instructions in embedding/README.md

tutorials/embedding/README.md

@@ -19,17 +19,19 @@ unzip -p source-archive.zip  word2vec/trunk/questions-words.txt > questions-word
 rm text8.zip source-archive.zip
 ```
 
-You will need to compile the ops as follows:
+You will need to compile the ops as follows (See 
+[Adding a New Op to TensorFlow](https://www.tensorflow.org/how_tos/adding_an_op/#building_the_op_library)
+for more details).:
 
 ```shell
-TF_INC=$(python -c 'import tensorflow as tf; print(tf.sysconfig.get_include())')
-g++ -std=c++11 -shared word2vec_ops.cc word2vec_kernels.cc -o word2vec_ops.so -fPIC -I $TF_INC -O2 -D_GLIBCXX_USE_CXX11_ABI=0
+TF_CFLAGS=( $(python -c 'import tensorflow as tf; print(" ".join(tf.sysconfig.get_compile_flags()))') )
+TF_LFLAGS=( $(python -c 'import tensorflow as tf; print(" ".join(tf.sysconfig.get_link_flags()))') )
+g++ -std=c++11 -shared word2vec_ops.cc word2vec_kernels.cc -o word2vec_ops.so -fPIC ${TF_CFLAGS[@]} ${TF_LFLAGS[@]} -O2 -D_GLIBCXX_USE_CXX11_ABI=0
 ```
 
-On Mac, add `-undefined dynamic_lookup` to the g++ command.
+On Mac, add `-undefined dynamic_lookup` to the g++ command. The flag `-D_GLIBCXX_USE_CXX11_ABI=0` is included to support newer versions of gcc. However, if you compiled TensorFlow from source using gcc 5 or later, you may need to exclude the flag. Specifically, if you get an error similar to the following: `word2vec_ops.so: undefined symbol: _ZN10tensorflow7strings6StrCatERKNS0_8AlphaNumES3_S3_S3_` then you likely need to exclude the flag.
 
-(For an explanation of what this is doing, see the tutorial on [Adding a New Op to TensorFlow](https://www.tensorflow.org/how_tos/adding_an_op/#building_the_op_library). The flag `-D_GLIBCXX_USE_CXX11_ABI=0` is included to support newer versions of gcc. However, if you compiled TensorFlow from source using gcc 5 or later, you may need to exclude the flag.)
-Then run using:
+Once you've successfully compiled the ops, run the model as follows:
 
 ```shell
 python word2vec_optimized.py \