[Cython] Problems in Py 3.0.1

[Stefan Behnel]

Stefan Behnel wrote:
> I also noticed tons of warnings in the C++ "compile" tests regarding
> useless code. I'm not sure why they pop up in Py3 and not in Py2.

Those are actually due to the refnanny code. I had to disable the refnanny
in Py3, as we cannot currently compile Cython on that platform anyway, and
the refnanny is built as part of the normal Cython build.

Stefan