Add OCaml Oasis

OCaml Oasis is a configure/build/install system for OCaml proget (like
Cabal for Haskell).

This commit also add a few small dependencies that where missing

  -  OCaml Data Notation (odn)
  -  ocamlify
  -  ocamlmod

pkgs/development/tools/ocaml/ocamlmod/default.nix

@@ -0,0 +1,25 @@
+{stdenv, fetchurl, ocaml, findlib, ounit}:
+
+stdenv.mkDerivation {
+  name = "ocamlmod-0.0.7";
+
+  src = fetchurl {
+    url = http://forge.ocamlcore.org/frs/download.php/1350/ocamlmod-0.0.7.tar.gz;
+    sha256 = "11kg7wh0gy492ma5c6bcjh6frv1a9lh9f26hiys2i0d1ky8s0ad3";
+  };
+
+  buildInputs = [ocaml findlib ounit];
+
+  configurePhase = "ocaml setup.ml -configure --prefix $out";
+  buildPhase     = "ocaml setup.ml -build";
+  installPhase   = "ocaml setup.ml -install";
+
+  meta = {
+    homepage = http://forge.ocamlcore.org/projects/ocamlmod/ocamlmod;
+    description = "Generate OCaml modules from source files";
+    platforms = ocaml.meta.platforms;
+    maintainers = with stdenv.lib.maintainers; [
+      z77z
+    ];
+  };
+}