C++ PATCH for c++/4286

[Jason Merrill]

>>>>> "Mark" == Mark Mitchell <mark@codesourcery.com> writes:

>> Would anyone complain about tearing out the xref code entirely?  It's been
>> dead code for about 10 years now.

> Please take it out.  I've been wanting to do this for years, but I thought
> you might not want me to do so. :-)

:)

No, I have no fondness for the xref code; it's been dead since before I
started working on the compiler.  I think the only person who ever touched
it was tiemann.  The only reason it has lived so long was the idea that it
might someday serve as the basis for something more useful, but now we have
something more useful (the tree dumper) which isn't based on the xref
stuff, so it can go away.

Rend!  Dismember!  Hack!

Jason