-Dgnu_{linux,hurd}

[Roland McGrath]

> > How about also getting rid of all nonreserved predefined symbols, on the
> > mainline?  (And deprecating them in the 3.1 release notes.)  Users have
> > known since 1989 that symbols in the reserved namespaces should be used,
> > e.g. __unix__ not unix.
> 
> I agree with this suggestion.

That would be a major incompatible change and I would not want my
observation about the recent addition of gnu_linux/gnu_hurd to be conflated
with the issue of the previously-existing predefiend names.  Nothing
anywhere has ever once used gnu_linux or gnu_hurd before, so we can fix
those now without any chance of compatibility worry.  I'm not really
interested in the issue of whether unix et al should go, that's between you
folks and the users.