That required a refactoring the timestamper feature. And the
explanation why is quite long... Let's do it.
The CGAL triangulations use the `Rebind_TDS` feature. During the
instanciation of `Compact_container<T>` it is important that `T` is
allowed to be incomplete, otherwise the circular dependencies between
TDS and Vertex/Cell cannot be resolved by the compiler. In previous
implementation of the timestamper, to allow `T` to be an incomplete
type, the compact container only carried a *point* to the time
stamper, allocated on the heap. A moved-from compact container would
only be valid if one recreated a time stamper for it on the head in
the move-constructor. As I want move operations to be `noexcept`, I
needed to change that implementation. Now the triangulation always
carries a time stamp counter (`std::size`), independently of the type
`T`, and the time stamper is an empty class, with static methods. That
allows `T` to be incomplete during the declaration of
`Compact_container<T>`.
Laurent Rineau
e82ea5de96