Re: allow benign typedef redefinitions (C11)

On 2025-Sep-19, Tom Lane wrote:

> Sooner or later we need to work out a subsystem hierarchy that
> can define which headers should be allowed to include which
> other ones.  I have no clear ideas about what that should look
> like, but I think the need for it gets ever more urgent.

I agree, we should do that.  In the meantime, it would help if people
were a tiny bit more careful with what headers they add to other
headers.

Here's a proposed fix.

-- 
Álvaro Herrera         PostgreSQL Developer  —  https://www.EnterpriseDB.com/
 It does it in a really, really complicated way
 why does it need to be complicated?
 Because it's MakeMaker.