[Checkins] [zopefoundation/persistent] ee72e1: Add the ability to force use of C extensions.

[Jason Madden]

  Branch: refs/heads/issue131
  Home:   https://github.com/zopefoundation/persistent
  Commit: ee72e13137a21dd62340513141b360de94ecf4e0
      https://github.com/zopefoundation/persistent/commit/ee72e13137a21dd62340513141b360de94ecf4e0
  Author: Jason Madden <jamadden at gmail.com>
  Date:   2020-02-25 (Tue, 25 Feb 2020)

  Changed paths:
    M .travis.yml
    M CHANGES.rst
    M persistent/__init__.py
    M persistent/_compat.py
    M persistent/cPersistence.c
    M persistent/persistence.py
    M persistent/picklecache.py
    M persistent/ring.py
    M persistent/tests/test_persistence.py
    M persistent/tests/test_picklecache.py
    M persistent/tests/test_timestamp.py
    M persistent/tests/utils.py
    M persistent/timestamp.py
    M setup.py
    M tox.ini

  Log Message:
  -----------
  Add the ability to force use of C extensions.

With PURE_PYTHON=0, like in zope.interface.

Also always require all three extensions. This solves mysterious issues you can get if you wind up mixing and matching (#124).

Fixes #131

Add travis and tox tests for this.


  Commit: 67e410f07bc7f999937574f18d9ec4e8e0498977
      https://github.com/zopefoundation/persistent/commit/67e410f07bc7f999937574f18d9ec4e8e0498977
  Author: Jason Madden <jamadden at gmail.com>
  Date:   2020-02-25 (Tue, 25 Feb 2020)

  Changed paths:
    M .travis.yml
    M appveyor.yml
    M tox.ini

  Log Message:
  -----------
  Force all CPython CI builds to require functioning C extensions, and simplify tox.ini.


Compare: https://github.com/zopefoundation/persistent/compare/4192cd3216a7...67e410f07bc7