[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.

3 files changed, 3 insertions, 3 deletions

diff --git a/tactics/btermdn.ml b/tactics/btermdn.ml
index a476381b17..70819e9550 100644
--- a/tactics/btermdn.ml
+++ b/tactics/btermdn.ml
@@ -29,7 +29,7 @@ type term_label =
 
 let compare_term_label t1 t2 = match t1, t2 with
 | GRLabel gr1, GRLabel gr2 -> GlobRef.Ordered.compare gr1 gr2
-| _ -> Pervasives.compare t1 t2 (** OK *)
+| _ -> pervasives_compare t1 t2 (** OK *)
 
 type 'res lookup_res = 'res Dn.lookup_res = Label of 'res | Nothing | Everything
 
diff --git a/tactics/class_tactics.ml b/tactics/class_tactics.ml
index 303ddacb67..849ea7e83f 100644
--- a/tactics/class_tactics.ml
+++ b/tactics/class_tactics.ml
@@ -257,7 +257,7 @@ let clenv_of_prods poly nprods (c, clenv) gl =
     let sigma = Tacmach.New.project gl in
     let ty = Retyping.get_type_of (Proofview.Goal.env gl) sigma c in
     let diff = nb_prod sigma ty - nprods in
-    if Pervasives.(>=) diff 0 then
+    if (>=) diff 0 then
       (* Was Some clenv... *)
       Some (Some diff,
             mk_clenv_from_n gl (Some diff) (c,ty))
diff --git a/tactics/redops.ml b/tactics/redops.ml
index e0473cbefd..86ed8f8899 100644
--- a/tactics/redops.ml
+++ b/tactics/redops.ml
@@ -10,7 +10,7 @@
 
 open Genredexpr
 
-let union_consts l1 l2 = Util.List.union Pervasives.(=) l1 l2 (* FIXME *)
+let union_consts l1 l2 = Util.List.union (=) l1 l2 (* FIXME *)
 
 let make_red_flag l =
   let rec add_flag red = function