[Distutils] setuptools: site_dirs

With easy_install I can specify --site-dirs to make it setup package with .pth files. But with setuptools alone I can't, particularly "python setup.py develop". I'm not sure if there's a setting in distutils.cfg I could use...? There doesn't seem to be any appropriate command-line option. I'm also not sure how the site directories are identified...? In this case, on Debian, /usr/local/lib/pythonX.Y/site-packages isn't recognized as such a directory, even after I added it with site.addsitedir in sitecustomize. Ian