Fix build on ocaml-4.00.1

Signed-off-by: Jon Ludlam <jonathan.ludlam@citrix.com>
CP-9206: Replace hard-coded paths with a search path

Signed-off-by: Jon Ludlam <jonathan.ludlam@citrix.com>
Merge pull request #94 from jonludlam/CP-9206

CP-9206