message: Fix ambiguous call to apply on FreeBSD
diff: #include "caf/byte.hpp"
  #include "caf/byte_buffer.hpp"
  +#include "caf/detail/squashed_int.hpp"
  #include "caf/error_code.hpp"
  #include "caf/fwd.hpp"
  #include "caf/read_inspector.hpp"
  @@ -127,7 +128,9 @@ public:
  template <class T>
  std::enable_if_t<std::is_integral<T>::value && std::is_signed<T>::value>
  apply(T x) {
  - return apply(static_cast<std::make_unsigned_t<T>>(x));
  + using unsigned_type = std::make_unsigned_t<T>;
  + using squashed_unsigned_type = detail::squashed_int_t<unsigned_type>;
  + return apply(static_cast<squashed_unsigned_type>(x));
  }
  template <class Enum>
  