libsupc++

[Benjamin Kosnik]

Actually, I think the naming is a step in the right direction. It was
pointed out at the time that many other compiler vendors do something similar,
either calling it a "c++ runtime lib" or a "c++ support library" or
whatever. 

The idea of moving C++ runtime support into its own library is a
fundamentally sound design decision, IMHO. It makes playing around
with binary-incompatible flags way way way easier.

-benjamin