The AutoInstaller doesn't work with HomeBrew Python at the moment. I'm pretty sure that the AutoInstaller is broken inside some virtualenvs for the same reason.
Created attachment 408747 [details]
HomeBrew sets a default install prefix which ends up conflicting with --home. We just need to override it when calling setup.py.
Comment on attachment 408747 [details]
(Rubberstamp, but... sure!)
Committed r267056: <https://trac.webkit.org/changeset/267056>