[galaxy-dev] setup_venv doesn't honour set_environment_for_install / installing lxml

In a tool_dependency.xml file I want to install python package lxml in a virtual environment, as a tool I'm building needs it. The python lxml package requires the libxml2 tool dependency. I have added a set_environment_for_install action that refers to the libxml2 repository, but when python/pip tries to install lxml it fails, apparently because it can't find the required headers. This appears to be because the setup_virtualenv action does not include install environment variables.

It seems to me that install environment variables should be sourced for every following action that can do nontrivial things, not just shell commands.

Alternatively, am I trying to install lxml the wrong way, is there a better way? (I'm running on python 2.6)

Jan