C++ ABI testing issues, gcc-3.3 <-> gcc-3.2 compatibility

[Benjamin Kosnik]

>> Nope, I'm suggesting
>> --enable-threads=posix --enable-shared --enable-__cxa_atexit
>> to be the default for linux native (or linux targets including 
>> cross?).

> That has been long overdue. I don't think there should be a difference
> between native and cross here.

Ditto. I'm in support of Jakub's configuration, as above, as the default
for linux systems.

Note that the solaris build has defaulted to threaded by default for
quite some time.

-benjamin