Lines taking from the asynchronous processing of stdout/stderr where
left as str, leading to encoding problems when utf8 characters showed
up in the stream and were being interpreted as ascii encoding.
(cherry picked from commit 9373be3)
Doesn't work reliably across pip versions, and adding a special rule for each and every version also isn't fun. Plugin authors will need to use a different approach for pulling in dependencies that are not on pypi during install, e.g. extra install urls or something like that. For now, I give up here ;)
