diff --git a/src/lib.ml b/src/lib.ml
index fb7cbe41..1a755ae7 100644
--- a/src/lib.ml
+++ b/src/lib.ml
@@ -383,6 +383,12 @@ end)
 module L = struct
   type nonrec t = t list
 
+  let to_iflags dirs =
+    Arg_spec.S
+      (Path.Set.fold dirs ~init:[] ~f:(fun dir acc ->
+         Arg_spec.Path dir :: A "-I" :: acc)
+       |> List.rev)
+
   let include_paths ts ~stdlib_dir =
     let dirs =
       List.fold_left ts ~init:Path.Set.empty ~f:(fun acc t ->
@@ -391,24 +397,34 @@ module L = struct
     Path.Set.remove dirs stdlib_dir
 
   let include_flags ts ~stdlib_dir =
-    let dirs = include_paths ts ~stdlib_dir in
-    Arg_spec.S (List.concat_map (Path.Set.to_list dirs) ~f:(fun dir ->
-      [Arg_spec.A "-I"; Path dir]))
+    to_iflags (include_paths ts ~stdlib_dir)
 
-  let c_include_flags ts ~stdlib_dir =
+  let c_include_paths ts ~stdlib_dir =
     let dirs =
       List.fold_left ts ~init:Path.Set.empty ~f:(fun acc t ->
         Path.Set.add acc t.src_dir)
     in
-    let dirs = Path.Set.remove dirs stdlib_dir in
-    Arg_spec.S (List.concat_map (Path.Set.to_list dirs) ~f:(fun dir ->
-      [Arg_spec.A "-I"; Path dir]))
+    Path.Set.remove dirs stdlib_dir
+
+  let c_include_flags ts ~stdlib_dir =
+    to_iflags (c_include_paths ts ~stdlib_dir)
 
   let link_flags ts ~mode ~stdlib_dir =
     Arg_spec.S
       (c_include_flags ts ~stdlib_dir ::
        List.map ts ~f:(fun t -> Arg_spec.Deps (Mode.Dict.get t.archives mode)))
 
+  let compile_and_link_flags ~compile ~link ~mode ~stdlib_dir =
+    let dirs =
+      Path.Set.union
+        (  include_paths compile ~stdlib_dir)
+        (c_include_paths link    ~stdlib_dir)
+    in
+    Arg_spec.S
+      (to_iflags dirs ::
+       List.map link ~f:(fun t ->
+         Arg_spec.Deps (Mode.Dict.get t.archives mode)))
+
   let jsoo_runtime_files ts =
     List.concat_map ts ~f:(fun t -> t.jsoo_runtime)
 
diff --git a/src/lib.mli b/src/lib.mli
index 6a312386..d42b4cbd 100644
--- a/src/lib.mli
+++ b/src/lib.mli
@@ -58,6 +58,13 @@ module L : sig
 
   val link_flags : t -> mode:Mode.t -> stdlib_dir:Path.t -> _ Arg_spec.t
 
+  val compile_and_link_flags
+    :  compile:t
+    -> link:t
+    -> mode:Mode.t
+    -> stdlib_dir:Path.t
+    -> _ Arg_spec.t
+
   (** All the library archive files (.a, .cmxa, _stubs.a, ...)  that
       should be linked in when linking an executable. *)
   val archive_files : t -> mode:Mode.t -> ext_lib:string -> Path.t list