message: Upgrade to C++17
  Summary:
  Pull Request resolved:
  Following a recent Redex move to C++17.
diff: @@ -10,8 +10,8 @@ function(print_dirs var name)
  endfunction()
  macro(set_common_cxx_flags_for_sparta)
  - message(STATUS "Using C++14")
  - set(CMAKE_CXX_STANDARD 14)
  + message(STATUS "Using C++17")
  + set(CMAKE_CXX_STANDARD 17)
  set(CMAKE_CXX_STANDARD_REQUIRED ON)
  set(CMAKE_CXX_EXTENSIONS OFF)
  if (MSVC)
  