libstdc++ compatibility

[Jeffrey A Law]

  In message < Pine.LNX.4.04.9810181406440.2394-100000@alien.devel.redhat.com >
  > you write:
  > <shame on>
  > Distribute a binary from egcs 1.0.3 package.
  > </shame>
Ok.

So, in the future if you could build these old libstdc++ releases with a 
new compiler and get something that is compatible for code which linked
against the old libstdc++ you'd be OK?

We certainly can't do it yet, but it might be something we can pull off in
the future.

The question in my mind is how can we test this functionality?  Just being
able to build the old library isn't enough, we have to verify to some extent
that it is compatible with the old one.

We've also got to get a handle on when we actually make incompatible changes.
We've started thinking about that some, but not enough IMHO.

Thoughts anyone?

jeff