`detail/invoke.hpp` fails to compile due to `std::result_of`

[vittorioromeo]

external/boost.context+/include/boost/context/detail/invoke.hpp:29:19: error: no type named 'result_of' in namespace 'std'
   29 |     typename std::result_of< Fn &&( Args && ... ) >::type
      |     ~~~~~~~~~~~~~~^~~~~~~~~
external/boost.context+/include/boost/context/detail/invoke.hpp:30:1: error: expected unqualified-id
   30 | >::type
      | ^
external/boost.context+/include/boost/context/detail/invoke.hpp:38:19: error: no type named 'result_of' in namespace 'std'
   38 |     typename std::result_of< Fn &&( Args && ... ) >::type
      |     ~~~~~~~~~~~~~~^~~~~~~~~
external/boost.context+/include/boost/context/detail/invoke.hpp:39:1: error: expected unqualified-id
   39 | >::type
      | ^