merge changes from version/4.00 from 4.00.1 to r13697

git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@13699 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02
testsuite/lib-threads: version of test8 that seems to work on Windows

git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@13700 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02