> What about PYTHON_OPT and allowing to pass any options via an environment > > variable? There is a number of precedences (gzip, less, etc).
>
>    export PYTHON_OPT="-t -b -3"

I'd be open to this, but it seems like a much wider change than something that I'd have time to build in time for Python 2.7.12.  I agree that this is a better long term direction (similarly, I'd like to enable the `-bb` flag in Python 3).  I'd have to put a bunch of thought into how this would merge with command line flags.

> Or PYTHON3COMP[ATIBILITY]?

I'm open to whichever.  lemburg had suggested `PYTHON3WARNINGS` so that's what I went with.  If that's a blocker for this patch happy to change it.