PR#5712: (6) document OCAMLRUNPARAM flag R

git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@13198 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02
PR#5712: (6) document OCAMLRUNPARAM flag R

git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@13199 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02