fix package requires order

Signed-off-by: ArthurW <arthur@tarides.com>

Author: art-w

src/dune_rules/lib.ml

@@ -1285,9 +1285,12 @@ end = struct
                "expected Virtual or Parameter"
                [ "implements", to_dyn impl ])
       in
-      List.concat [ requires_implements; requires_params; requires ]
-      |> Set.of_list
-      |> Set.to_list
+      let requires = List.concat [ requires_implements; requires_params; requires ] in
+      let _, requires =
+        List.fold_left requires ~init:(Set.empty, []) ~f:(fun (seen, lst) lib ->
+          if Set.mem seen lib then seen, lst else Set.add seen lib, lib :: lst)
+      in
+      List.rev requires
     in
     let resolve_impl impl_name =
       let open Resolve.Memo.O in