exception handling and conservative GC

[Benjamin Kosnik]

I agree that the in-flight exceptions issue is problematic. 

I actually have a patch somewhere that tracks this stuff and attempts
to cleanly de-allocate. Much like the arm-eabi hooks.

However, some of this has changed since 4.0.x. In particular, mainline
and 4.1 have some of these issues fixed: I suggest using and or testing
with these versions.

See:
libstdc++/23591

-benjamin