[MLton] Bug in MLton.Pointer on amd64

[Florian Weimer]

This program

  val false = MLton.Pointer.sub (MLton.Pointer.null, 0w1)
	      = MLton.Pointer.add (MLton.Pointer.null, 0w1)

should run without output, but it raises the Bind exception instead.
It appears that

  MLton.Pointer.sub (MLton.Pointer.null, 0w1)

is not the all-ones address, but the address 0x1.