message: Make typed_actor<> comparable to actor
diff: #include <cstddef>
  -#include "caf/intrusive_ptr.hpp"
  -
  +#include "caf/actor.hpp"
  #include "caf/make_actor.hpp"
  #include "caf/actor_cast.hpp"
  #include "caf/replies_to.hpp"
  #include "caf/actor_system.hpp"
  +#include "caf/intrusive_ptr.hpp"
  #include "caf/composed_type.hpp"
  #include "caf/abstract_actor.hpp"
  #include "caf/stateful_actor.hpp"
  @@ -56,6 +56,7 @@ class typed_broker;
  /// parameter pack.
  template <class... Sigs>
  class typed_actor : detail::comparable<typed_actor<Sigs...>>,
  + detail::comparable<typed_actor<Sigs...>, actor>,
  detail::comparable<typed_actor<Sigs...>, actor_addr>,
  detail::comparable<typed_actor<Sigs...>, strong_actor_ptr> {
  public:
  @@ -232,6 +233,10 @@ class typed_actor : detail::comparable<typed_actor<Sigs...>>,
  return actor_addr::compare(get(), x.get());
  }
  + intptr_t compare(const actor& x) const noexcept {
  + return actor_addr::compare(get(), actor_cast<actor_control_block*>(x));
  + }
  +
  intptr_t compare(const actor_addr& x) const noexcept {
  return actor_addr::compare(get(), actor_cast<actor_control_block*>(x));
  }
  