Relaxing sphinx requirement

[jakirkham]

I know this may come across as a strange request, but is there a way of relaxing and/or removing the sphinx requirement. This is causing some of us build trouble with sphinx ( sphinx-doc/sphinx#1845 ).

[agjohnson]

This might not be too far fetched, I don't know of anything requiring us to specify sphinx as a dependency. This would be worth exploring and possibly removing the requirement.

[birkenfeld]

It's probably the most pragmatic way out of this circular dependency (which shouldn't cause problems, but apparently too many build tool authors are unaware of the distinction between build-time and run-time dependencies).