changing include/g++-v3 to something a bit more obvious

[Benjamin Kosnik]

>     Phil> There's already an 'include' subdir; we could just make it
>     Phil> 'include/g++' and let the pathname speak for itself.
> 
> The difficulty here is that, in theory, if we actually get the C++ ABI
> stable (which it's supposed to be after 3.0), you might want to use
> the same old library with a brand-new compiler.  (Why?  Because the
> library ABI is bound to change; it's not fully done yet.  So, if you
> want to use a new compiler with better optimization, etc., but still
> produce link-compatible stuff you might stick with the old library.)

right. Thanks for giving this implementor flexibility WRT to the API....

> I agree that making -V actually work would be terrfic, so I think on
> balance I like Phil's suggestion.  It's going to need discussion on
> the GCC lists, and possibly even with the SC, though; I can't decide
> this unilaterally.

this makes at least three of us...... since this is going to change soon 
anyway, this might be a good time to do it.

Note that most of the actual work is aready done, (see the 
--enable-version-specific-runtime-libs configure option here:
http://sources.redhat.com/libstdc++/configopts.html )

-benjamin