diff -uNr async_unix-113.33.00/_oasis async_unix-113.33.00+4.03/_oasis
--- async_unix-113.33.00/_oasis	2016-03-09 16:44:52.000000000 +0100
+++ async_unix-113.33.00+4.03/_oasis	2016-03-22 15:13:48.000000000 +0100
@@ -1,8 +1,8 @@
 OASISFormat:           0.4
-OCamlVersion:          >= 4.02.3
+OCamlVersion:          >= 4.03.0
 FindlibVersion:        >= 1.3.2
 Name:                  async_unix
-Version:               113.33.00
+Version:               113.33.00+4.03
 Synopsis:              Monadic concurrency library
 Authors:               Jane Street Group, LLC <opensource@janestreet.com>
 Copyrights:            (C) 2008-2016 Jane Street Group LLC <opensource@janestreet.com>
diff -uNr async_unix-113.33.00/opam async_unix-113.33.00+4.03/opam
--- async_unix-113.33.00/opam	2016-03-18 12:08:01.000000000 +0100
+++ async_unix-113.33.00+4.03/opam	2016-03-22 17:51:33.000000000 +0100
@@ -26,4 +26,4 @@
   "typerep"
   "variantslib"
 ]
-available: [ ocaml-version >= "4.02.3" ]
+available: [ ocaml-version >= "4.03.0" ]
diff -uNr async_unix-113.33.00/src/raw_scheduler.ml async_unix-113.33.00+4.03/src/raw_scheduler.ml
--- async_unix-113.33.00/src/raw_scheduler.ml	2016-03-09 16:44:52.000000000 +0100
+++ async_unix-113.33.00+4.03/src/raw_scheduler.ml	2016-03-22 15:13:48.000000000 +0100
@@ -587,7 +587,7 @@
 
 let sync_changed_fds_to_file_descr_watcher t =
   let module F = (val t.file_descr_watcher : File_descr_watcher.S) in
-  let make_file_descr_watcher_agree_with (fd : Fd.t) =
+  let make_file_descr_watcher_agree_with = (fun (fd : Fd.t) ->
     fd.watching_has_changed <- false;
     let desired =
       Read_write.mapi fd.watching ~f:(fun read_or_write watching ->
@@ -607,7 +607,7 @@
     with exn ->
       failwiths "sync_changed_fds_to_file_descr_watcher unable to set fd"
         (desired, fd, exn, t) [%sexp_of: bool Read_write.t * Fd.t * exn * t]
-  in
+  ) [@inline always] in
   let changed = t.fds_whose_watching_has_changed in
   t.fds_whose_watching_has_changed <- [];
   List.iter changed ~f:make_file_descr_watcher_agree_with;
diff -uNr async_unix-113.33.00/src/std.ml async_unix-113.33.00+4.03/src/std.ml
--- async_unix-113.33.00/src/std.ml	2016-03-09 16:44:52.000000000 +0100
+++ async_unix-113.33.00+4.03/src/std.ml	2016-03-22 15:13:48.000000000 +0100
@@ -60,10 +60,9 @@
 
   module Overwrite_ = struct
     let overwrite1 (`This_is_async__Think_about_blocking as x) = x
-    let wrap f `This_is_async__Think_about_blocking = f
-    let overwrite2 = wrap overwrite1
-    let overwrite3 = wrap overwrite2
-    let overwrite4 = wrap overwrite3
+    let overwrite2 `This_is_async__Think_about_blocking = overwrite1
+    let overwrite3 `This_is_async__Think_about_blocking = overwrite2
+    let overwrite4 `This_is_async__Think_about_blocking = overwrite3
     let overwritef f = ksprintf (fun _ -> `This_is_async__Think_about_blocking) f
   end
   open Overwrite_
diff -uNr async_unix-113.33.00/src/unix_syscalls.ml async_unix-113.33.00+4.03/src/unix_syscalls.ml
--- async_unix-113.33.00/src/unix_syscalls.ml	2016-03-09 16:44:52.000000000 +0100
+++ async_unix-113.33.00+4.03/src/unix_syscalls.ml	2016-03-22 15:13:48.000000000 +0100
@@ -365,8 +365,8 @@
 ;;
 
 (* symlinks *)
-let symlink ~src ~dst =
-  In_thread.syscall_exn ~name:"symlink" (fun () -> Unix.symlink ~src ~dst)
+let symlink ?to_dir ~src ~dst =
+  In_thread.syscall_exn ~name:"symlink" (fun () -> Unix.symlink ?to_dir ~src ~dst)
 ;;
 
 let readlink filename =
diff -uNr async_unix-113.33.00/src/unix_syscalls.mli async_unix-113.33.00+4.03/src/unix_syscalls.mli
--- async_unix-113.33.00/src/unix_syscalls.mli	2016-03-09 16:44:52.000000000 +0100
+++ async_unix-113.33.00+4.03/src/unix_syscalls.mli	2016-03-22 15:13:48.000000000 +0100
@@ -223,7 +223,7 @@
   -> string
   -> unit Deferred.t
 
-val symlink : src:string -> dst:string -> unit Deferred.t
+val symlink : ?to_dir:bool -> src:string -> dst:string -> unit Deferred.t
 
 val readlink : string -> string Deferred.t