Update gevent to 1.4.0

[pyup-bot]

This PR updates gevent from 1.3.7 to 1.4.0.

Changelog

1.4.0

==================

- Build with Cython 0.29 in '3str' mode.

- Test with PyPy 6.0 on Windows.

- Add support for application-wide callbacks when ``Greenlet`` objects
are started. See :pr:`1289`, provided by Yury Selivanov.

- Fix consuming a single ready object using
``next(gevent.iwait(objs))``. Previously such a construction would
hang because `iter` was not called. See :pr:`1288`, provided by Josh
Snyder. This is not recommended, though, as unwaited objects will
have dangling links (but see next item).

- Make `gevent.iwait` return an iterator that can now also be used as
a context manager. If you'll only be consuming part of the iterator,
use it in a ``with`` block to avoid leaking resources. See
:pr:`1290`, provided by Josh Snyder.

- Fix semaphores to immediately notify links if they are ready and
``rawlink()`` is called. This behaves like ``Event`` and
``AsyncEvent``. Note that the order in which semaphore links are
called is not specified. See :issue:`1287`, reported by Dan Milon.

- Improve safety of handling exceptions during interpreter shutdown.
See :issue:`1295` reported by BobDenar1212.

- Remove the deprecated ability to specify ``GEVENT_RESOLVER`` and
other importable settings as a ``path/to/a/package.module.item``.
This had race conditions and didn't work with complicated resolver
implementations. Place the required package or module on `sys.path`
first.

- Reduce the chances that using the blocking monitor functionality
could result in apparently random ``SystemError:
Objects/tupleobject.c: bad argument to internal function``. Reported
in :issue:`1302` by Ulrich Petri.

- Refactored the gevent test runner and test suite to make them more
reusable. In particular, the tests are now run with ``python -m
gevent.tests``. See :issue:`1293`.

- Make a monkey-patched ``socket.getaddrinfo`` return socket module
enums instead of plain integers for the socket type and address
family on Python 3. See :issue:`1310` reported by TheYOSH.

- Make gevent's pywsgi server set the non-standard environment value
``wsgi.input_terminated`` to True. See :issue:`1308`.

- Make `gevent.util.assert_switches` produce more informative messages
when the assertion fails.

- Python 2: If a `gevent.socket` was closed asynchronously (in a
different greenlet or a hub callback), `AttributeError` could result
if the socket was already in use. Now the correct socket.error
should be raised.

- Fix :meth:`gevent.threadpool.ThreadPool.join` raising a
`UserWarning` when using the libuv backend. Reported in
:issue:`1321` by ZeroNet.

- Fix ``FileObjectPosix.seek`` raising `OSError` when it should have
been `IOError` on Python 2. Reported by, and PR by, Ricardo Kirkner.
See :issue:`1323`.

- Upgrade libuv from 1.23.2 to 1.24.0.

Links

• PyPI: https://pypi.org/project/gevent
• Changelog: https://pyup.io/changelogs/gevent/
• Homepage: http://www.gevent.org/