Sigh!  I was hoping we could get this in for 3.7.0 but I think we have run out of time and we really should not be making potential user-visible API changes at this last minute.  I did notice the new compile warning for the Windows non-debug build but I overlooked that some other non-Windows buildbots were getting them, too.  Serihy proposes a more general fix in Issue33818 but I don't think we should be making a change like that just prior to the release candidate.

And, in retrospect, I should not have considered trying to fix the stable ABI support at this late date, either. It looks like it has been broken for some time now so 3.7.0 will not be any worse.  At this point, we have Christian's two PRs in master now; if necessary, they could be reverted.  I will bow out of this discussion and let you all figure out what is best for master/3.8.  Once the changes for master are in and working, we could revisit the question of backports to 3.7 and/or 3.6 maintenance releases. I would like to both thank and apologize to Christian, in particular, and to Serhiy and everyone else who went out of their ways to try to get this in.

Lowering priority to "critical".