IMHO the most important question to answer first is: Why is adding OSF1 support a good idea?

The PR, which IMHO in its current state is not mergeable, adds some complexity to the build and ongoing maintenance of CPython itself.  This tends to be acceptable for in-use and maintained operating systems, but is a lot less so for hardware and operating systems that are basically museum pieces. 

So, why do you want to run bleeding edge CPython on such hardware?

And as Terry mentioned this is something that should be discussed on python-dev, not on the tracker.


A secondary, but still important, question is the support question.  A fairly recent discussion on Solaris support should give some insight as to what's required there: https://mail.python.org/archives/list/python-dev@python.org/thread/VDD7NMEDFXMOP4S74GEYJUHJRJPK2UR3/.   And note that OpenSolaris appears to be a lot more actively used and supported than OSF1.