That's a preliminary report I made a couple of days ago. I posted it on G+ for some friends, it got re-posted by the official Python account and gone viral on Twitter.
The interview is tonight. Coverity is probably going to create their own report after the interview.
The "save_errno" approach is a common technique and not a hack. On modern systems with threading support the errno variable is a carefully crafted macro that wraps an internal function + thread local storage. Several Python files like signalmodule, faulthandler and more are using save_errno.
Yes, we are pedantic. Sometimes it's not easy to cope with but we are creating a hell of a shiny piece of software. :)