Doc.

git-svn-id: http://caml.inria.fr/svn/ocaml/branches/extension_points@13537 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02
Remove pcsig_loc field + doc.

git-svn-id: http://caml.inria.fr/svn/ocaml/branches/extension_points@13538 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02
Doc.

git-svn-id: http://caml.inria.fr/svn/ocaml/branches/extension_points@13539 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02