update reference file for tests/lib-printf

git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@13615 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02
tests/callback: do not run when libunix is not configured

git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@13616 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02
testsuite: better reporting of failed tests

git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@13617 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02