Regarding my question above, with Richard Wackerbarth's help, I have resolved my issue. The issue is that if one is running in an active virtualenv, with sphinx installed globally but not in the virtualenv, you have to either install sphinx in the virtualenv or run setup with the global python, e.g. '/usr/bin/python setup.py build_sphinx'.
Regarding my question above, with Richard Wackerbarth's help, I have resolved my issue. The issue is that if one is running in an active virtualenv, with sphinx installed globally but not in the virtualenv, you have to either install sphinx in the virtualenv or run setup with the global python, e.g. '/usr/bin/python setup.py build_sphinx'.