[Patch, libstdc++/68877] Reimplement __is_[nothrow_]swappable

[Jonathan Wakely]

On 23/12/15 22:15 +0100, Daniel Krügler wrote:
>
>    PR libstdc++/68877
>    * include/std/type_traits: Following N4511, reimplement __is_swappable and
>    __is_nothrow_swappable. Move __is_swappable to namespace std, adjust
>    callers. Use __is_nothrow_swappable in swap.
>    * include/bits/move.h: Use __is_nothrow_swappable in swap.
>    * testsuite/20_util/is_nothrow_swappable/value.cc: Extend; remove
>    __is_swappable related tests.
>    * testsuite/20_util/is_swappable/value.cc: New.
>    * testsuite/20_util/is_swappable/requirements/explicit_instantiation.cc:
>    New.
>    * testsuite/20_util/is_swappable/requirements/typedefs.cc: New.
>    * testsuite/25_algorithms/swap/68877.cc: New.

Committed to trunk now, thanks!