[patch] Make std::tr1::shared_ptr thread-safe.

[Paolo Carlini]

Jonathan Wakely wrote:

>Ouch.  First of all, thanks for the review, Peter.
>  
>
Yes, many thanks from me too.

>I think my patch should be applied anyway, as it's an improvement, and
>these other problems can be tackled one by one.  I have a lot of reading
>to do so I can get up to speed on these issues!
>  
>
Personally, I'm ok with this kind of stewise improvement, but, in case
we cannot
really meet the thread-safety expectations in time for 4.0.0, we should
document
the issue somewhere.

Paolo.