[Bug c/67479] Support for -Wformat-pedantic

[manu at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67479

--- Comment #4 from Manuel López-Ibáñez <manu at gcc dot gnu.org> ---
(In reply to joseph@codesourcery.com from comment #3)
> This should not be a pedwarn, because it only has undefined behavior in 
> ISO C at runtime, not compile time.

But it is enabled by -pedantic -Wformat (and not -Wformat). Moreover, it is
enabled by -pedantic-errors -Wformat (but not as an error), which is confusing.