[Bug target/91148] PowerPC build gets several warnings due to -Wformat-diag

[segher at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91148

--- Comment #9 from Segher Boessenkool <segher at gcc dot gnu.org> ---
Let me put it differently, then:

Such warnings should not be enabled by default before most it warns about
has been fixed.