sig
  type t =
      External
    | Available_externally
    | Link_once
    | Link_once_odr
    | Link_once_odr_auto_hide
    | Weak
    | Weak_odr
    | Appending
    | Internal
    | Private
    | Dllimport
    | Dllexport
    | External_weak
    | Ghost
    | Common
    | Linker_private
    | Linker_private_weak
end