Use ocamldep -all option.

In v2v, 'stringMap.ml' has no corresponding *.mli file.  ocamldep does
not generate a *.cmi dependency for such modules, and this can result
in parallel builds failing rarely because:

 (1) stringMap.ml is built (which has the side-effect of generating
     stringMap.cmi)

 (2) at the same time, types.mli is compiled.  types.mli depends on
     stringMap.cmi, but it is half way through being created by (1).

There is no dependency to serialize (1) and (2).

The resulting error is:

  File "types.mli", line 1:
  Error: Corrupted compiled interface
  stringMap.cmi

Using 'ocamldep -all' generates extra deps for the *.cmi files, and
otherwise appears to be safe, so use it.

There are currently a few upstream OCaml bugs with dependencies and
parallel builds:

http://caml.inria.fr/mantis/view.php?id=3190
http://caml.inria.fr/mantis/view.php?id=4991
http://caml.inria.fr/mantis/view.php?id=5000

It's not clear which of these apply here.