Straightened up the selection of installation directories for platform-   specific files; it was somewhat broken, and the comments were dead   wrong. Now runs 'install_ext' command after 'install_py'.
Straightened up the selection of installation directories for platform-
  specific files; it was somewhat broken, and the comments were dead
  wrong.
Now runs 'install_ext' command after 'install_py'.

pypa/setuptools,pypa/setuptools,pypa/setuptools