Revert "Remove use of setup_requires. Builders now require pip 10 or later to build/install from sdist. Older installers will still install the packages from wheels. Ref tox-dev/tox#809."
Revert "Remove use of setup_requires. Builders now require pip 10 or later to build/install from sdist. Older installers will still install the packages from wheels. Ref tox-dev/tox#809."

This reverts commit 2c91e8ec0d99f9ca354b7f913d61720925bb98bc.

jaraco/jaraco.collections,pwdyson/inflect.py,jaraco/jaraco.text,jaraco/jaraco.itertools,python/importlib_metadata,jaraco/jaraco.context,jaraco/jaraco.functools,yougov/pmxbot,yougov/librarypaste,pytest-dev/pytest-runner,hugovk/inflect.py,jaraco/rwt,jaraco/jaraco.stream,yougov/librarypaste,jaraco/jaraco.logging,jaraco/calendra,yougov/pmxbot,yougov/pmxbot,jaraco/tempora,jaraco/hgtools,jaraco/portend,jazzband/inflect,jaraco/jaraco.classes,jaraco/zipp,jaraco/backports.functools_lru_cache,jaraco/keyring,jaraco/irc,jaraco/jaraco.path