[PATCH users/roland/gold-charnn] gold: Use char16_t, char32_t instead of uint16_t, uint32_t as character types

[Cary Coutant]

> The std::basic_string template type is only specified for
> instantiations using character types.  Newer (LLVM) libc++
> implementations no longer allow non-character integer types
> to be used.
>
> Ok for trunk?

LGTM. Thanks!

-cary