C++ ABI Issues

[Benjamin Kosnik]

I'll restrain my comments to one area only.

Please, let's use the versioning info that already exists. Currently,
the compiler ABI is tracked with __GXX_ABI_VERSION. For the 3.2.0
release, this value is 102.

If there is to be a -fabi=xxx switch, then please use this information.
The idea of having a "-fabi-newest" is completely relative and useless:
newest from what vantage point? 

-benjamin