buildDunePackage: new support function; use it to refactor some OCaml derivations

pkgs/development/ocaml-modules/ocaml-migrate-parsetree/default.nix

@@ -1,30 +1,22 @@
-{ stdenv, fetchFromGitHub, ocaml, findlib, ocamlbuild, dune, result }:
+{ stdenv, fetchFromGitHub, buildDunePackage, result }:
 
-if !stdenv.lib.versionAtLeast ocaml.version "4.02"
-then throw "ocaml-migrate-parsetree is not available for OCaml ${ocaml.version}"
-else
-
-stdenv.mkDerivation rec {
-   name = "ocaml${ocaml.version}-ocaml-migrate-parsetree-${version}";
+buildDunePackage rec {
+   pname = "ocaml-migrate-parsetree";
    version = "1.1.0";
 
    src = fetchFromGitHub {
      owner = "ocaml-ppx";
-     repo = "ocaml-migrate-parsetree";
+     repo = pname;
      rev = "v${version}";
      sha256 = "1d2n349d1cqm3dr09mwy5m9rfd4bkkqvri5i94wknpsrr35vnrr1";
    };
 
-   buildInputs = [ ocaml findlib ocamlbuild dune ];
    propagatedBuildInputs = [ result ];
 
-   inherit (dune) installPhase;
-
    meta = {
      description = "Convert OCaml parsetrees between different major versions";
      license = stdenv.lib.licenses.lgpl21;
      maintainers = [ stdenv.lib.maintainers.vbgl ];
      inherit (src.meta) homepage;
-     inherit (ocaml.meta) platforms;
    };
 }