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

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

@@ -1,33 +1,24 @@
-{ stdenv, fetchFromGitHub, ocaml, findlib, dune
-, angstrom, faraday, alcotest
-}:
+{ stdenv, fetchFromGitHub, buildDunePackage, angstrom, faraday, alcotest }:
 
-stdenv.mkDerivation rec {
+buildDunePackage rec {
+  pname = "httpaf";
   version = "0.4.1";
-  name = "ocaml${ocaml.version}-httpaf-${version}";
 
   src = fetchFromGitHub {
     owner = "inhabitedtype";
-    repo = "httpaf";
+    repo = pname;
     rev = version;
     sha256 = "0i2r004ihj00hd97475y8nhjqjln58xx087zcjl0dfp0n7q80517";
   };
 
-  buildInputs = [ ocaml findlib dune alcotest ];
+  buildInputs = [ alcotest ];
   propagatedBuildInputs = [ angstrom faraday ];
-
-  buildPhase = "dune build -p httpaf";
-
   doCheck = true;
-  checkPhase = "dune runtest -p httpaf";
-
-  inherit (dune) installPhase;
 
   meta = {
     description = "A high-performance, memory-efficient, and scalable web server for OCaml";
     license = stdenv.lib.licenses.bsd3;
     maintainers = [ stdenv.lib.maintainers.vbgl ];
     inherit (src.meta) homepage;
-    inherit (ocaml.meta) platforms;
   };
 }