[RFA] Algorithms vs operator* and operator==

[Paolo Carlini]

Paolo Carlini wrote:

> Can you spot anything wrong with this kind of change? If we agree that
> it's good, there are quite a few places to tweak, both in stl_algo and
> in stl_algobase (besides locale_facets ;)

*But*, now I remember std::fill and std::fill_n: in order to avoid expensive
copies when _ValueType is "big", we should probably use temporary vars
(like __value) *only* when __is_scalar<_ValueType>::_M_type is true...

Paolo.