1 files changed, 4 insertions, 3 deletions
diff --git a/nixpkgs/pkgs/development/ocaml-modules/facile/default.nix b/nixpkgs/pkgs/development/ocaml-modules/facile/default.nix
index df228603e9f4..3eab7d3417fc 100644
--- a/nixpkgs/pkgs/development/ocaml-modules/facile/default.nix
+++ b/nixpkgs/pkgs/development/ocaml-modules/facile/default.nix
@@ -1,11 +1,9 @@
-{ lib, fetchurl, buildDunePackage }:
+{ lib, fetchurl, buildDunePackage, ocaml }:
 
 buildDunePackage rec {
   pname = "facile";
   version = "1.1.4";
 
-  useDune2 = false;
-
   src = fetchurl {
     url = "https://github.com/Emmanuel-PLF/facile/releases/download/${version}/facile-${version}.tbz";
     sha256 = "0jqrwmn6fr2vj2rrbllwxq4cmxykv7zh0y4vnngx29f5084a04jp";
@@ -13,6 +11,9 @@ buildDunePackage rec {
 
   doCheck = true;
 
+  useDune2 = lib.versionAtLeast ocaml.version "4.12";
+  postPatch = lib.optionalString useDune2 "dune upgrade";
+
   meta = {
     homepage = "http://opti.recherche.enac.fr/facile/";
     license = lib.licenses.lgpl21Plus;