[Bug c/67819] -Wduplicated-cond should take macros into account

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67819

--- Comment #3 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Yeah, exactly; this problem will require some significant effort, I'm afraid
>:(.