[Bug c++/86971] -Wabi warns it will not warn about anything.

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86971

--- Comment #5 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Richard Biener from comment #4)
> ?  Btw, is that true when I use -fabi-version=11 -Wabi?

That will give warnings.

-Wabi (with no =n value) is only useless without an explicit -fabi-version,
because it means "warn about incompatibilities with the default -fabi-version".
If you don't use -fabi-version then you're using the default, and so there are
no differences.