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

pkgs/development/ocaml-modules/ipaddr/default.nix

@@ -1,21 +1,16 @@
-{ stdenv, fetchurl, ocaml, ocamlbuild, findlib
-, dune, sexplib, ppx_sexp_conv
-}:
+{ stdenv, fetchurl, buildDunePackage, sexplib, ppx_sexp_conv }:
 
-stdenv.mkDerivation rec {
-  name = "ocaml${ocaml.version}-ipaddr-${version}";
+buildDunePackage rec {
+  pname = "ipaddr";
   version = "2.8.0";
 
   src = fetchurl {
-    url = "https://github.com/mirage/ocaml-ipaddr/archive/${version}.tar.gz";
+    url = "https://github.com/mirage/ocaml-${pname}/archive/${version}.tar.gz";
     sha256 = "1amb1pbm9ybpxy6190qygpj6nmbzzs2r6vx4xh5r6v89szx9rfxw";
   };
 
-  buildInputs = [ ocaml findlib ocamlbuild dune ];
   propagatedBuildInputs = [ ppx_sexp_conv sexplib ];
 
-  inherit (dune) installPhase;
-
   meta = with stdenv.lib; {
     homepage = https://github.com/mirage/ocaml-ipaddr;
     description = "A library for manipulation of IP (and MAC) address representations ";