turn on {!Sys.backend_type} (works)

Author: bobzhang

stdlib/sys.mli

@@ -93,9 +93,9 @@ val os_type : string
 - ["Win32"] (for MS-Windows, OCaml compiled with MSVC++ or Mingw),
 - ["Cygwin"] (for MS-Windows, OCaml compiled with Cygwin). *)
 
-(* val backend_type : backend_type *)
+val backend_type : backend_type
 (** Backend type currently executing the OCaml program. 
- @ since 4.03.0
+ @ since 4.04.0
  *)
 
 val unix : bool

stdlib/sys.mlp

@@ -32,11 +32,11 @@ external max_wosize : unit -> int = "%max_wosize"
 external unix : unit -> bool = "%ostype_unix"
 external win32 : unit -> bool = "%ostype_win32"
 external cygwin : unit -> bool = "%ostype_cygwin"
-(* external get_backend_type : unit -> backend_type = "%backend_type" *)
+external get_backend_type : unit -> backend_type = "%backend_type"
 
 let (executable_name, argv) = get_argv()
 let (os_type, _, _) = get_config()
-(* let backend_type = get_backend_type () *)
+let backend_type = get_backend_type ()
 let big_endian = big_endian ()
 let word_size = word_size ()
 let int_size = int_size ()