functional, split tr1 and c++0x impl's ?

[Paolo Carlini]

> Thoughts?

As soon as you have evidence than ~10 ifdefs are required just split, split, split. This tr1_impl idea, suggested by Doug, is very nice, IMO, because it allows for a smooth transition to the C++0x specifications, but as soon as we have evidence that C++0x is appreciably different, let's just split and obtain something much more clean even if a little redundant.

By the way, you may have noticed my recent suggestion about shared_ptr to Jonathan, he is right now splitting it...

Paolo.