[v3] c++0x timed wait's in <condition_variable>

[Paolo Carlini]

Hi again, Chris ,
> This patch solves the issue with solution B.
>   
I say, for gcc4.4.0, let's go ahead with Plan B. We can certainly
improve things later.

Only, please confirm that the additional exports are in any case needed
if we want a separate monotonic clock, regtest again the patch vs
current mainline and commit it.

Thanks again,
Paolo.