Somehow I missed to cvs add the pkg and patches directories.

Thanks to Björn Ketelaars for telling me.

net/unison/patches/patch-ubase_util_ml

@@ -0,0 +1,18 @@
+$OpenBSD: patch-ubase_util_ml,v 1.1 2014/10/17 06:22:08 chrisz Exp $
+
+The Uprintf module is broken since OCaml 4.02.
+The OCaml stdlib provides a similar function since 3.09.
+Use this function instead.
+
+--- ubase/util.ml.orig	Fri Sep 19 12:38:42 2014
++++ ubase/util.ml	Fri Sep 19 12:39:27 2014
+@@ -62,7 +62,8 @@ let set_infos s =
+   if s <> !infos then begin clear_infos (); infos := s; show_infos () end
+ 
+ let msg f =
+-  clear_infos (); Uprintf.eprintf (fun () -> flush stderr; show_infos ()) f
++  clear_infos ();
++  Printf.kfprintf (fun _ -> flush stderr; show_infos ()) stderr f
+ 
+ let msg : ('a, out_channel, unit) format -> 'a = msg
+ 

net/unison/patches/patch-uicommon_ml

@@ -0,0 +1,26 @@
+$OpenBSD: patch-uicommon_ml,v 1.1 2014/10/17 06:22:08 chrisz Exp $
+
+Don't discard backtraces for uncaught exceptions.
+
+--- uicommon.ml.orig	Tue Sep 23 11:23:39 2014
++++ uicommon.ml	Tue Sep 23 11:37:20 2014
+@@ -309,7 +309,8 @@ let reconItem2string oldPath theRI status =
+   let (r1, action, r2, path) = reconItem2stringList oldPath theRI in
+   Format.sprintf "%s %s %s %s %s" r1 (action2niceString action) r2 status path
+ 
+-let exn2string = function
++let exn2string exn = 
++  let s = match exn with
+     Sys.Break      -> "Terminated!"
+   | Util.Fatal(s)  -> Printf.sprintf "Fatal error: %s" s
+   | Util.Transient(s) -> Printf.sprintf "Error: %s" s
+@@ -323,6 +324,9 @@ let exn2string = function
+          | _                  -> "")
+   | Invalid_argument s -> Printf.sprintf "Invalid argument: %s" s
+   | other -> Printf.sprintf "Uncaught exception %s" (Printexc.to_string other)
++  in
++  s ^
++  if Printexc.backtrace_status () then "\n" ^ Printexc.get_backtrace () else ""
+ 
+ (* precondition: uc = File (Updates(_, ..) on both sides *)
+ let showDiffs ri printer errprinter id =

net/unison/pkg/DESCR

@@ -0,0 +1,8 @@
+Unison is a file-synchronization tool for Unix and Windows.  It allows
+two replicas of a collection of files and directories to be stored on
+different hosts (or different disks on the same host), modified
+separately, and then brought up to date by propagating the changes in
+each replica to the other.
+
+Flavors:
+	no_x11 	- build without X support

net/unison/pkg/PLIST

@@ -0,0 +1,9 @@
+@comment $OpenBSD: PLIST,v 1.4 2014/10/17 06:22:08 chrisz Exp $
+@pkgpath net/unison/stable${FLAVOR_COMMA}
+@pkgpath net/unison/snapshot${FLAVOR_COMMA}
+@bin bin/unison
+share/doc/pkg-readmes/${FULLPKGNAME}
+share/doc/unison/
+share/doc/unison/BUGS.txt
+share/doc/unison/NEWS
+share/doc/unison/README

net/unison/pkg/README

@@ -0,0 +1,12 @@
+$OpenBSD: README,v 1.1 2014/10/17 06:22:08 chrisz Exp $
+
++-----------------------------------------------------------------------
+| Running ${FULLPKGNAME} on OpenBSD
++-----------------------------------------------------------------------
+
+Unison uses native OCaml marshalling in its prococol. This
+means that unison might not work when the OCaml versions of
+two instances are out of sync.
+One way to work around this limitation of unison is to use
+the OPAM OCaml package and compiler manager to sync the
+OCaml versions on your machines.