Remove special case for OCaml 4.08

parsetree_show/dune

@@ -3,15 +3,3 @@
   (public_name override.parsetree_show)
   (preprocess (staged_pps override ppxlib.metaquot ppx_deriving.std))
   (libraries compiler-libs.common))
-
-(rule
-  (targets parsetree_show.ml)
-  (deps parsetree_show.cppo.ml)
-  (action
-     (run %{bin:cppo} -V OCAML:%{ocaml_version} %{deps} -o %{targets})))
-
-(rule
-  (targets parsetree_show.mli)
-  (deps parsetree_show.cppo.mli)
-  (action
-     (run %{bin:cppo} -V OCAML:%{ocaml_version} %{deps} -o %{targets})))
\ No newline at end of file

parsetree_show/parsetree_show.cppo.ml → parsetree_show/parsetree_show.ml

-#if OCAML_VERSION >= (4, 07, 0) && OCAML_VERSION < (4, 09, 0)
-  module%override Stdlib = struct
-    module%override Lexing = struct
-      type position = _ [@@deriving show]
-    end
-  end
-#else
-  module%override Lexing = struct
-    type position = _ [@@deriving show]
-  end
-#endif
+module%override Lexing = struct
+  type position = _ [@@deriving show]
+end
 
 module%override Longident = struct
   [%%types] [@@deriving show]

parsetree_show/parsetree_show.cppo.mli → parsetree_show/parsetree_show.mli

-#if OCAML_VERSION >= (4, 07, 0) && OCAML_VERSION < (4, 09, 0)
-  module%override Stdlib : sig
-    module%override Lexing : sig
-      type position = _ [@@rewrite] [@@deriving show]
-    end
-  end
-#else
-  module%override Lexing : sig
-    type position = _ [@@rewrite] [@@deriving show]
-  end
-#endif
+module%override Lexing : sig
+  type position = _ [@@rewrite] [@@deriving show]
+end
 
 module%override Longident : sig
   [%%types] [@@deriving show]