libstdc++ c++98 & c++11 ABI incompatibility

[Jason Merrill]

On 06/14/2012 06:14 AM, Matthias Klose wrote:
> While PR53646 claims that c++98 and c++11 should be ABI
> compatible (modulo bugs), the addition of the _M_size member
> to std::_List_base::_List_impl makes libraries using
> std::list in headers incompatible, when built in c++98 and
> c++11 mode.

So it does.  That change should not have gone into 4.7 without having a 
plan to deal with the consequences.  I thought we weren't going to mess 
with ABI-breaking changes like this yet...

Jason