Getting Apple's libstdc++ debug mode into the FSF tree

[B. Kosnik]

>The library is called libstdc++, we link with 
>-lstdc++, and it's the library for the C++ language.

True, true: -debug=libstdc++ it is then. I'm still not quite what to do
about the concept checking bits, but Phil will know the current status
on that bit.

-benjamin