Issue #17386 make.bat must run with Python 2 until Sphinx runs with Python 3.
If PYTHON is undefined, this fails without the launcher (installed with 3.3 or
from PyPI), but this is better than always failing. Patch from Zachary Ware.
Issue #1285086: Get rid of the refcounting hack and speed up
urllib.parse.unquote() and urllib.parse.unquote_to_bytes().