[core] [api] Support OCaml 4.08

The changes are large due to `Pervasives` deprecation:

- the `Pervasives` module has been deprecated in favor of `Stdlib`, we
  have opted for introducing a few wrapping functions in `Util` and
  just unqualified the rest of occurrences. We avoid the shims as in
  the previous attempt.

- a bug regarding partial application have been fixed.

- some formatting functions have been deprecated, but previous
  versions don't include a replacement, thus the warning has been
  disabled.

We may want to clean up things a bit more, in particular
w.r.t. modules once we can move to OCaml 4.07 as the minimum required
version.

Note that there is a clash between 4.08.0 modules `Option` and `Int`
and Coq's ones. It is not clear if we should resolve that clash or
not, see PR #10469 for more discussion.

On the good side, OCaml 4.08.0 does provide a few interesting
functionalities, including nice new warnings useful for devs.

1 files changed, 2 insertions, 2 deletions

diff --git a/lib/pp.ml b/lib/pp.ml
index 542e5f6ecd..2f780677d9 100644
--- a/lib/pp.ml
+++ b/lib/pp.ml
@@ -197,9 +197,9 @@ let pp_with ft pp =
     | Ppcmd_print_break(m,n)  -> pp_print_break ft m n
     | Ppcmd_force_newline     -> pp_force_newline ft ()
     | Ppcmd_comment coms      -> List.iter (pr_com ft) coms
-    | Ppcmd_tag(tag, s)       -> pp_open_tag  ft tag;
+    | Ppcmd_tag(tag, s)       -> pp_open_tag  ft tag [@warning "-3"];
                                  pp_cmd s;
-                                 pp_close_tag ft ()
+                                 pp_close_tag ft () [@warning "-3"]
   in
   try pp_cmd pp
   with reraise ->