[Distutils] Odd limitation in packaging/distutils2

[Éric Araujo]

Hi Paul,

> PS D:\Data\PyPI> D:\Data\cpython\PCbuild\python -m packaging.run install nose
> installing third-party projects from an uninstalled Python is not supported
There is a comment in the source to explain that:

  # Python would try to install into the site-packages directory under
  # $PREFIX, but when running from an uninstalled code checkout we don't
  # want to create directories under the installation root

(Original bug report: #12246)

> And yet after downloading the nose source...
> [snip]
Ah, I need to reopen the bug.  The patch edited d2.install but forgot to
touch the install_commands.

Regards