[Bug ipa/82094] Improve diagnostics about target specific option mismatch

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82094

--- Comment #5 from Martin Liška <marxin at gcc dot gnu.org> ---
(In reply to Richard Biener from comment #4)
> Probably requires the target hook to also return a diagnostic substring.

We have #define TARGET_OPTION_PRINT ix86_function_specific_print
which is quite close what we would need.