Log Message:
Update to 0.23.4:

0.23.4 (2015-10-10)
===================

Bugs fixed
----------

* Memory leak when calling Python functions in PyPy.

* Compilation problem with MSVC in C99-ish mode.

* Warning about unused values in a helper macro.

0.23.3 (2015-09-29)
===================

Bugs fixed
----------

* Invalid C code for some builtin methods.  This fixes ticket 856 again.

* Incorrect C code in helper functions for PyLong conversion and string
  decoding.  This fixes ticket 863, ticket 864 and ticket 865.
  Original patch by Nikolaus Rath.

* Large folded or inserted integer constants could use too small C
  integer types and thus trigger a value wrap-around.

Other changes
-------------

* The coroutine and generator types of Cython now also register directly
  with the ``Coroutine`` and ``Generator`` ABCs in the ``backports_abc``
  module if it can be imported.  This fixes ticket 870.