ocaml-atdgen: add minimal version (1.6.0) to the system

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

@@ -0,0 +1,25 @@
+{stdenv, atd, yojson, menhir, easy-format, biniou, cppo, buildOcaml, fetchurl, which}:
+
+buildOcaml rec {
+  name = "atdgen";
+  version = "1.6.0";
+
+  src = fetchurl {
+    url = "https://github.com/mjambon/atdgen/archive/v${version}.tar.gz";
+    sha256 = "1icdxgb7qqq1pcbfqi0ikryiwaljd594z3acyci8g3bnlq0yc7zn";
+  };
+
+  installPhase = ''
+    mkdir -p $out/bin
+    make PREFIX=$out install
+  '';
+
+  buildInputs = [ which atd biniou yojson ];
+
+  meta = with stdenv.lib; {
+    homepage = https://github.com/mjambon/atdgen;
+    description = "Generates optimized boilerplate OCaml code for JSON and Biniou IO from type definitions";
+    license = licenses.bsd3;
+    maintainers = [ maintainers.jwilberding ];
+  };
+}

pkgs/top-level/all-packages.nix

@@ -4064,6 +4064,9 @@ let
     async = callPackage ../development/ocaml-modules/async { };
 
     atd = callPackage ../development/ocaml-modules/atd { };
+
+    atdgen = callPackage ../development/ocaml-modules/atdgen { };
+
     base64 = callPackage ../development/ocaml-modules/base64 { };
 
     bolt = callPackage ../development/ocaml-modules/bolt { };