[patch-rfc] N2179: Exception Propagation in C++

[Sebastian Redl]

Hi,

My copyright assignment should have arrived by now, so I'll try again to 
get feedback on this.

The attached patch implements the C++ proposal N2179: Exception 
Propagation. It modifies the exception handling to support the 
std::current_exception() and std::rethrow_exception() calls.

Read more here:
http://gcc.gnu.org/ml/libstdc++/2008-07/msg00062.html

Patch should apply cleanly against the trunk as of July 18, 13:30 GMT.

Some particular points I need feedback about:
How do I deal with gnu.ver correctly? Where exactly should my new 
functions go?
I need to test the behavior of some of features in a multi-threaded 
environment. How do I write such tests?
Any special considerations for ARM unwinding that I don't understand but 
need to address?

Sebastian