Comment 0 for bug 1387768

Cython is widely used. It would be useful to describe the recommended way to use pbr alongside Cython (if such a way exists). Currently I've added an sdist pre-hook to warn if the .c (or .cpp) files that have Cython .pyx files are not generated. This seems like a sufficient safe guard against shipping code but it does not allow other tools to work, such as tox.