Build with OCaml 5.4 (#2717)

This doesn't make OCamlformat able to format 5.4 code.

Author: Julow

CHANGES.md

@@ -6,6 +6,10 @@ profile. This started with version 0.26.0.
 
 ## unreleased
 
+### Added
+
+- Support for OCaml 5.4 (#2717, @Julow)
+
 ### Deprecated
 
 - Starting in this release, ocamlformat can use cmdliner >= 2.0.0. When that is

lib/bin_conf/Bin_conf.ml

@@ -523,11 +523,9 @@ let update_using_env conf =
 let discard_formatter =
   Format.(
     formatter_of_out_functions
-      { out_string= (fun _ _ _ -> ())
-      ; out_flush= (fun () -> ())
-      ; out_newline= (fun () -> ())
-      ; out_spaces= (fun _ -> ())
-      ; out_indent= (fun _ -> ()) } )
+      { (get_formatter_out_functions ()) with
+        out_string= (fun _ _ _ -> ())
+      ; out_flush= (fun () -> ()) } )
 
 let global_lib_term =
   Term.(