CCInt32(chore): add condition around functions existing in newer OCaml

src/core/CCInt32.ml

@@ -2,9 +2,18 @@
 
 include Int32
 
+[@@@iflt 4.13]
+
 let min : t -> t -> t = Stdlib.min
 let max : t -> t -> t = Stdlib.max
+
+[@@@endif]
+[@@@iflt 5.1]
+
 let hash x = Stdlib.abs (to_int x)
+
+[@@@endif]
+
 let sign i = compare i zero
 
 let pow a b =

src/core/CCInt32.mli

@@ -18,6 +18,8 @@ include module type of struct
   include Int32
 end
 
+[@@@iflt 4.13]
+
 val min : t -> t -> t
 (** [min x y] returns the minimum of the two integers [x] and [y].
     @since 3.0 *)
@@ -26,10 +28,15 @@ val max : t -> t -> t
 (** [max x y] returns the maximum of the two integers [x] and [y].
     @since 3.0 *)
 
+[@@@endif]
+[@@@iflt 5.1]
+
 val hash : t -> int
 (** [hash x] computes the hash of [x].
     Like {!Stdlib.abs (to_int x)}. *)
 
+[@@@endif]
+
 val sign : t -> int
 (** [sign x] return [0] if [x = 0], [-1] if [x < 0] and [1] if [x > 0].
     Same as [compare x zero].