fix missing archs

git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@14798 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02
mark PR#5580 as potentially breaking change

git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@14799 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02