CFFI 38 has been a great success so far in Python. Did you consider using it for interfacing C code?
There are many benefits of CFFI, just to mention few:

Abstract the Python version (CPython2, CPython3, PyPy).
Better control over when and why the C compilation occurs, and more standard ways to write setuptools-based setup.py 3 files.
Keep all the Python-related logic in Python so that you don’t need to write much C code.