[c++0x] <date_time> implementation, take 4

[Paolo Carlini]

Hi Pedro,
> Fixed function definitions to uglify local names.
>
> Fixed testsuite to use --std=gnu++0x instead of --std=c++0x.
Excellent.
> make check FAILs only abi_check.
Mind, it should not! The only possible explanation is that you didn't 
update lately the compiler proper...  (Honza fixed an inlining issue 
which lead to spurious abi_check fails) Can you double check?

Paolo.