MLton 20210117

# MLtonItimer

    signature MLTON_ITIMER =
       sig
          datatype t =
             Prof
           | Real
           | Virtual

          val set: t * {interval: Time.time, value: Time.time} -> unit
          val signal: t -> Posix.Signal.signal
       end

- set (t, {interval, value})

  sets the interval timer (using setitimer) specified by t to the given interval and value.

- signal t

  returns the signal corresponding to t.