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

pkgs/development/ocaml-modules/lwt/4.x.nix

@@ -1,35 +1,29 @@
-{ stdenv, fetchzip, pkgconfig, ncurses, libev, dune
-, ocaml, findlib, cppo
-, ocaml-migrate-parsetree, ppx_tools_versioned, result
+{ stdenv, fetchzip, pkgconfig, ncurses, libev, buildDunePackage, ocaml
+, cppo, ocaml-migrate-parsetree, ppx_tools_versioned, result
 }:
 
 let inherit (stdenv.lib) optional versionAtLeast; in
 
-stdenv.mkDerivation rec {
+buildDunePackage rec {
+  pname = "lwt";
   version = "4.1.0";
-  name = "ocaml${ocaml.version}-lwt-${version}";
 
   src = fetchzip {
-    url = "https://github.com/ocsigen/lwt/archive/${version}.tar.gz";
+    url = "https://github.com/ocsigen/${pname}/archive/${version}.tar.gz";
     sha256 = "16wnc61kfj54z4q8sn9f5iik37pswz328hcz3z6rkza3kh3s6wmm";
   };
 
   nativeBuildInputs = [ pkgconfig ];
-  buildInputs = [ ocaml findlib dune cppo
-    ocaml-migrate-parsetree ppx_tools_versioned
-  ] ++ optional (!versionAtLeast ocaml.version "4.07") ncurses;
+  buildInputs = [ cppo ocaml-migrate-parsetree ppx_tools_versioned ]
+   ++ optional (!versionAtLeast ocaml.version "4.07") ncurses;
   propagatedBuildInputs = [ libev result ];
 
   configurePhase = "ocaml src/util/configure.ml -use-libev true";
-  buildPhase = "jbuilder build -p lwt";
-  inherit (dune) installPhase;
 
   meta = {
     homepage = "https://ocsigen.org/lwt/";
     description = "A cooperative threads library for OCaml";
     maintainers = [ stdenv.lib.maintainers.vbgl ];
     license = stdenv.lib.licenses.lgpl21;
-    inherit (ocaml.meta) platforms;
   };
 }
-

pkgs/development/ocaml-modules/lwt/ppx.nix

@@ -1,19 +1,15 @@
-{ stdenv, dune, ocaml, findlib, lwt, ppx_tools_versioned }:
+{ stdenv, buildDunePackage, lwt, ppx_tools_versioned }:
 
-stdenv.mkDerivation {
-  name = "ocaml${ocaml.version}-lwt_ppx-${lwt.version}";
+buildDunePackage {
+  pname = "lwt_ppx";
 
-  inherit (lwt) src;
-
-  buildInputs = [ dune ocaml findlib ppx_tools_versioned ];
+  inherit (lwt) src version;
 
+  buildInputs = [ ppx_tools_versioned ];
   propagatedBuildInputs = [ lwt ];
 
-  buildPhase = "dune build -p lwt_ppx";
-  installPhase = "${dune.installPhase} lwt_ppx.install";
-
   meta = {
     description = "Ppx syntax extension for Lwt";
-    inherit (lwt.meta) license platforms homepage maintainers;
+    inherit (lwt.meta) license homepage maintainers;
   };
 }