[Distutils] Updates to PEP-513

[Nathaniel Smith]

Hi all,

Based on recent discussions, I'm proposing the following update to PEP 513:

https://github.com/pypa/manylinux/pull/31/files

The changes to the text are:

* Remove the UCS-4 requirement in favor of pip/wheel's new SOABI support.
* Mandate that manylinux1 extensions not link against
libpythonX.Y.so.1, for the complicated compatibility-related reasons
that were discussed on list.
* Update link for the docker images to their new PyPA home.

Comments welcome, of course.

I haven't sent this to the PEP editors yet, because I'm not sure if
there's any particular ceremony needed for changing the semantics of a
PEP that's already been pronounced upon?

-n

-- 
Nathaniel J. Smith -- https://vorpus.org