[GCC-XML]New cv-qualified type referencing scheme

[Brad King]

On Fri, 17 Oct 2003, Brad King wrote:

> I'll implement this change when I get a chance unless someone suggests a
> better approach.

I've implemented the change.  For now I've left the location attribute,
but it may be removed eventually.  Declaration location is now accessible
as

  file="f0" line="20"

-Brad