Keep std::deque algos specializations in Debug mode

[Jonathan Wakely]

On 25/08/18 22:44 +0200, François Dumont wrote:
>The last optimizations that get disabled when Debug mode is enable are 
>the algo specializations for std::deque iterators.
>
>This patch move those algos in std namespace as they should even when 
>Debug mode is enable so that they get considered even when calls are 
>made with the namespace qualification. And it adds all the algos Debug 
>implementations which forward to normal implementations to benefit 
>from optimizations.

Please add a ChangeLog to the patch.