Don't use buildOcaml

pkgs/build-support/ocaml/oasis.nix

@@ -1,10 +1,24 @@
-{ buildOcaml, ocaml_oasis }:
+{ stdenv, ocaml_oasis, ocaml, findlib, ocamlbuild, camlp4 }:
 
-{ buildInputs ? [], ...
+{ name, version, buildInputs ? [], meta ? { platforms = ocaml.meta.platforms or []; },
+  minimumOcamlVersion ? null,
+  createFindlibDestdir ? true,
+  dontStrip ? true,
+  hasSharedObjects ? false,
+  setupHook ? null,
+  ...
 }@args:
 
-buildOcaml (args // {
-  buildInputs = [ ocaml_oasis ] ++ buildInputs;
+ assert minimumOcamlVersion != null ->
+          stdenv.lib.versionOlder minimumOcamlVersion ocaml.version;
+
+stdenv.mkDerivation (args // {
+  name = "ocaml-${name}-${version}";
+
+  buildInputs = [ ocaml findlib ocamlbuild camlp4 ocaml_oasis ] ++ buildInputs;
+
+  inherit createFindlibDestdir;
+  inherit dontStrip;
 
   buildPhase = ''
     runHook preBuild
@@ -28,4 +42,11 @@ buildOcaml (args // {
     prefix=$OCAMLFIND_DESTDIR ocaml setup.ml -install
     runHook postInstall
   '';
+
+  setupHook = if setupHook == null && hasSharedObjects
+              then stdenv.writeText "setupHook.sh" ''
+              export CAML_LD_LIBRARY_PATH="''${CAML_LD_LIBRARY_PATH}''${CAML_LD_LIBRARY_PATH:+:}''$1/lib/ocaml/${ocaml.version}/site-lib/${name}/"
+              ''
+              else setupHook;
+
 })