[Bug c/86134] earlier diagnostic causes followup diagnostic about unknown -Wno-* options

[lopezibanez at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86134

--- Comment #7 from Manuel López-Ibáñez <lopezibanez at gmail dot com> ---
What I'm suggesting is to add an option to control this warning, which is
currently enabled by default. Then you can use -Wno-error or even -Wno- to
make it always a warning or completely disable it. This what clang does.