I see that there's yet another proposal for standardization of pragma once
on the agenda for C?
Is there any chance that this gets adopted? Because at scale it doesn't
work, and causes both structural and transient problems, and it will be
even harder to get people not to use it if it's in the standard.

The include guard replacement form would be OK, but also doesn't fix the
common complaints about guards, that it suffers from collision and
cut/paste errors.