libstdc++ compatibility issues with various Linux distros

[Benjamin Kosnik]

> I've run into what looks like a compatibility problem with the libstdc++ 
> library.   My code that's built with gcc 2.95.3 will not run properly on 
> RedHat 7.2.

Mmmm. Yeah. There is no ABI compatibility between 2.96 and 2.95.3. You
can't intermix these two C++ compilers and two C++ libstdc++'s and
expect things to work.

That's why we are working so hard on the ABI for 3.2.

-benjamin