[Bug c++/87404] Implement -Wenum-compare and -Wenum-compare-switch

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87404

--- Comment #1 from Martin Liška <marxin at gcc dot gnu.org> ---
It comes from Clang, where there's no documentation, only a warning message:

-Wenum-compare: comparison of two values with different enumeration types
-Wenum-compare-switch: comparison of two values with different enumeration
types in switch statement