pypa/pip — pull request #814 by jmcfarlane (2013-02-20 00:23:25+00:00)
Title: Fix build_prefix on osx (swing 2)

There was a recent fix (#768) for issue #707 that fixed the brew
install use case, but not the virtualenv use case. This commit
consolidates the logic. This was discovered when testing wheel
generation using qwcode's wheel_install branch.

Testing performed (simplejson, numpy 1.7):

- osx lion (using virtualenv)
- osx lion (installed via root)
- ubuntu lucid (using virtualenv)
- ubuntu lucid (installed via root)

Reference:
- https://github.com/pypa/pip/issues/707
- https://github.com/pypa/pip/pull/768