forked from microsoft/GSL
- A macro with the very generic name `BYTE_TYPE` is likely to collide with existing code, so get rid of the macro. - The new solution is to provide a non-deprecated `byte` in the namespace `gsl::impl`. - Users of GSL should use `gsl::byte`, which is still deprecated when mapped to a `std::std::byte`. - GSL types and functions need to use `gsl::impl::byte` so they do not trigger the deprecation warning. - The `gsl::impl::byte` return type in an exported function is not nice, it might mislead users to use that type in their own declarations. But the `BYTE_TYPE` solution is not better in this respect. Co-authored-by: Werner Henze <w.henze@avm.de>