ocamlPackages.lwt: 2.6.0 -> 2.7.1

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

@@ -1,19 +1,30 @@
 { stdenv, fetchzip, which, cryptopp, ocaml, findlib, ocamlbuild, camlp4
 , ocaml_react, ocaml_ssl, libev, pkgconfig, ncurses, ocaml_oasis, glib
-, ppx_tools, result
+, ppx_tools, result, cppo
 , ppxSupport ? stdenv.lib.versionAtLeast ocaml.version "4.02"
 }:
 
+let param =
+  if stdenv.lib.versionAtLeast ocaml.version "4.02"
+  then {
+    version = "2.7.1";
+    sha256 = "0w7f59havrl2fsnvs84lm7wlqpsrldg80gy5afpnpr21zkw22g8w";
+  } else {
+    version = "2.6.0";
+    sha256 = "0f1h83zh60rspm4fxd96z9h5bkhq1n1q968hgq92sq4a6bfi1c2w";
+  };
+in
+
 stdenv.mkDerivation rec {
   name = "ocaml-lwt-${version}";
-  version = "2.6.0";
+  inherit (param) version;
 
   src = fetchzip {
     url = "https://github.com/ocsigen/lwt/archive/${version}.tar.gz";
-    sha256 = "0f1h83zh60rspm4fxd96z9h5bkhq1n1q968hgq92sq4a6bfi1c2w";
+    inherit (param) sha256;
   };
 
-  buildInputs = [ ocaml_oasis pkgconfig which cryptopp ocaml findlib ocamlbuild glib ncurses camlp4 ]
+  buildInputs = [ ocaml_oasis pkgconfig which cryptopp ocaml findlib ocamlbuild glib ncurses camlp4 cppo ]
   ++ stdenv.lib.optional ppxSupport ppx_tools;
 
   propagatedBuildInputs = [ result ocaml_react ocaml_ssl libev ];