[Bug c/59850] Support sparse-style pointer address spaces (type attributes)

[josh at joshtriplett dot org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59850

--- Comment #13 from Josh Triplett <josh at joshtriplett dot org> ---
(In reply to H. Peter Anvin from comment #8)
> Arguably the *right* way to solve that would be to support __null for C as
> well as for C++.

__null or nullptr?