[PATCH] Fix libstdc++/6503

[Paolo Carlini]

Gabriel Dos Reis wrote:

>I would say there is no risk, but I would like people much more
>knowledgeable than I double check.  That is why I asked the question.
>
Ok.

I have also carried out a simple but convincing (in my understanding, at 
least) test: compiled deque_operators.cc with current 3.1.1 + my patch 
and then linking the resulting deque_operators.o with plain 3.1 and also 
viceversa.

By the way, I'm done with my merges from trunk, I will await closure on 
this ABI issue to move also the fix for 6503 to the branch.

Ciao, Paolo.