title: Can I set env vars for dependencies in setup-tools?
body: <p>Is it possible to set env vars to be used by dependencies set in the <code>setup.py</code> file of a package? </p>
  
  <p>Specifically; the <code>lxml</code> package is a dependency of one of my packages. To help ease deployment I want to set <code>STATIC_DEPS=true</code> and some CFLAGS for <code>lxml</code> in the setup.py file for my package, so that our users can just <code>easy_install my-package</code> without any install issues.</p>