Update readme.md

Add case for compiling ops if tensorflow was compiled from source using gcc >= 5.0

tutorials/embedding/README.md

@@ -26,6 +26,13 @@ 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
 ```
 
+If tensorflow was compiled from source using gcc >= 5.0, you don't need to append D_GLIBCXX_USE_CXX11_ABI=0.
+
+```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
+```
+
 On Mac, add `-undefined dynamic_lookup` to the g++ command.
 
 (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 g++.)