[Bug c++/53431] C++ preprocessor ignores #pragma GCC diagnostic

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53431

--- Comment #15 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Jeffrey Walton from comment #13)
> This issued caused Crypto++ to remove -Wall (and above) under GCC.

That seems to be throwing the baby out with the bathwater. Why not simply use

 -Wall -Wno-unused-value -Wno-unused-variable

?