[Bug c/81665] Please introduce flags attribute for enums which will mimic one from C#

[egallager at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81665

--- Comment #6 from Eric Gallager <egallager at gcc dot gnu.org> ---
Note that clang has __attribute__((flag_enum)):
https://clang.llvm.org/docs/AttributeReference.html#flag-enum