RFA: v3 PATCH to add on_quick_exit/quick_exit to std

[Benjamin De Kosnik]

> .. also, I think we should have #if __cplusplus >= 201103L protecting 
> these functions too, exactly like all the other C++11 bits. Eg, I
> don't think we should unconditionally, ie in C++03 mode too, declare 
> at_quick_exit and quick_exit in namespace std.

Yeah.
 
> I can tweak things for the two issues I noticed.

Thanks. 

It seems like this is still 4.8 material to me.

-benjamin