Remove algorithms implementation duplications

[Jonathan Wakely]

On 11 July 2012 19:52, François Dumont wrote:
>
>     Note also that this patch in addition to cleaning libstdc++ code will
> also benefit to our users:
>     - concept check are no repeated each time an algo call an other algo.
> Now concept checks are done in Standard algo implementations and those
> implementations only use internal functions, the "__XXX" functions, that do
> not redo the checks

That's good, although I'm not sure how many people actually use those
checks often.

Is there any noticeable difference when not using concept checks,
either to code size, compile time, or performance?

>     I also wonder if I shouldn't move all the implementation details in the
> std::__detail namespace ? Should I do it now, before eventually applying the
> patch ?

Yes, I think they are internal details, not GNU extensions or other
non-standard but user-visible components like some of the __gnu_cxx
contents.  Also, as Paolo pointed out, all the object generators in
<bits/predefined_ops.h> should be inline.

Overall I like the simplifications it makes to the algos, nice work.