How can Autoconf help with the transition to stricter compilation defaults?

[Michael Matz via cfe-commits]

Hello,

On Wed, 16 Nov 2022, Sam James wrote:

> Unrelated but I was a bit tempted to ask for throwing in 
> -Wbuiltin-declaration-mismatch to default -Werror while Clang 16 was at 
> it, but I suppose we don't want the world to burn too much,

:-)  It's IMHO a bug in the standard that it misses "if any of its 
associated headers are included" in the item for reservation of external 
linkage identifiers; it has that for all other items about reserved 
identifiers in the Library clause.  If that restriction were added you 
couldn't justify erroring on the example at hand (because it doesn't 
include e.g. <stdio.h> and then printf wouldn't be reserved).  A warning 
is of course always okay and reasonable.  As is, you could justify 
erroring out, but I too think that would be overzealous.


Ciao,
Michael.