module Flags_intf:sig..end
module Flags implements Unix-style sets of flags that are represented as
an int with various bits set, one bit for each flag. E.g. Linux_ext.Epoll.Flag.
Flags defines a module type Flags.S, the interface for a flags, and a functor
Flags.Make for creating a flags implementation.
module Int63: Int63module type S =sig..end
module type S is the interface for a set of flags.
module type Make_arg =sig..end
module type Flags =sig..end