When using license_file, setuptools prints a warning: “setuptools._deprecation_warning.SetuptoolsDeprecationWarning: The license_file parameter is deprecated, use license_files instead.”.

The license_files key was introduced in “wheel” package Git commit 59976ab294e1b118f42cab404d95df66ed55f7e4 from 2018-07-16. The disadvantage of this change is that when using wheel < 0.32.0, the resulting wheel will not contain the license file in its .dist-info directory.

Trying to make this test a little bit less fragile

Fix the test failures on hppa.  Thanks Stefano Rivera

A couple of years ago the libffi port for hppa-linux was changed from using a
trampoline executed on the stack to the function descriptor technique used by
ia64. This doesn't require an executable stack and is simpler. However,
function pointers need to have the PLABEL bit set in the pointer. As a result,
a simple cast can't be used to convert closure pointers to function pointers.

python-cffi uses its own closure allocation so the problem can't be fixed in
libffi.

I added a macro CFFI_FN to do the conversion. It shouldn't affect other
architectures. There is a similar define in libffi.

Fixes: https://bugs.debian.org/1024271

Incorrect brew installation setup

Two missing calls to PyObject_GC_UnTrack()

Drop py.code usage from tests, no longer depend on the deprecated py package

See merge request pypy/cffi!116