[Omake] OCamlPackage with .mli

[Michael Furr]

OCaml's -pack option allows you to include a .mli (technically, .cmi) to 
specify the interface of the resulting packed library.  However, omake 
doesn't seem to play nice in this situation.  Suppose I have:

   FILES[] = a b c
   $(OCamlPackage result, $(FILES))

This fails because it does not try to compile the file "result.mli" and 
thus ocamlopt sees an .mli but not .cmi.

If FILES[] includes "result", then omake fails with "deadlock on result.o. 
result.o is a dependency of result.o", thus making it impossible to use 
this feature with the current OCamlProgram function.

It would be great if the OCamlPackage build rule could be updated to take 
advantage of this feature.

Cheers,
-Mike