Link to gcc_s and gcc if compiler is GCC version 5 (#17849)

When using cmake and GCC 5.4 to build tensorflow in Ubuntu 16.04,
the following error message would show up when loading
_pywrap_tensorflow_internal.so:
```
_pywrap_tensorflow_internal.so: undefined symbol: __cpu_model
```

The root cause is the same to this issue:
https://github.com/tensorflow/tensorflow/issues/9593



Signed-off-by: Yihong Wang <yh.wang@ibm.com>