Log Message:
Update py-greenlet to 0.4.9:

0.4.9
=====
- Fixed Windows builds

0.4.8
=====
- Added support for iOS (arm32)
- Added support for ppc64le

0.4.7
=====
- Added a missing workaround for `return 0` on mips
- Restore compatibility with Python 2.5
- Fixed stack switching on sparc

0.4.6
=====
- Expose `_stack_saved` property on greenlet objects, it may be used to
  introspect the amount of memory used by a saved stack, but the API is
  subject to change in the future
- Added a workaround for `return 0` compiler optimizations on all
  architectures
- C API typo fixes

0.4.5
=====
- Fixed several bugs in greenlet C API
- Fixed a bug in multi-threaded applications, which manifested itself
  with spurious "cannot switch to a different thread" exceptions
- Fixed some crashes on arm and mips architectures

0.4.4
=====
- Fixed PyGreenlet_SetParent signature, thanks to BoonsNaibot
- Fixed 64-bit Windows builds depending on wrong runtime dll

0.4.3
=====
- Better slp_switch performance on SPARC
- Drop support for Python 2.3
- Fix trashcan assertions on debug builds of Python
- Remove deprecated -fno-tree-dominator-opts compiler switch
- Enable switch code for SunStudio on 32-bit SunOS
- Support for abc abstract methods in greenlet subclasses
- Support custom directories for tests
- Document switch tracing support

0.4.2
=====
- Add .travis.yml
- Fix 'err' may be used uninitialized in this function
- Check _MSC_VER for msvc specific code
- Fix slp_switch on SPARC for multi-threaded environments
- Add support for m68k