configure

#!/usr/bin/env ocaml
(* -*- tuareg -*- *)

type 'a value =
    | This of 'a
    | Auto

let string_of_value to_string = function
  | This a -> "This (" ^ to_string a ^ ")"
  | Auto -> "Auto"

let () =
  let declare_flag arg description =
    let reference = ref Auto in
    let args =
       [ "--enable-" ^ arg, Arg.Unit (fun () -> reference := This true),
         " Enable " ^ description
       ; "--disable-" ^ arg, Arg.Unit (fun () -> reference := This false),
         " Disable " ^ description
       ]
    in args, reference
   in
  let args_zlib, ref_zlib = declare_flag "zlib" "ZLib" in
  let args_hardware_support, ref_hardware_support =
    declare_flag "hardwaresupport"
                 "hardware support for AES and GCM (needs GCC or Clang)" in
  Arg.parse
    (Arg.align (args_zlib @ args_hardware_support))
    (fun s -> raise (Arg.Bad (Printf.sprintf "don't know what to do with %S" s)))
    "Usage: ./configure [OPTIONS]";
  let oc = open_out_bin "src/config/config_vars.ml" in
  Printf.fprintf oc {|
type 'a value =
    | This of 'a
    | Auto

let enable_zlib = %s
let enable_hardware_support = %s
|}
    (string_of_value string_of_bool !ref_zlib)
    (string_of_value string_of_bool !ref_hardware_support);
  close_out oc;
  (* Below is a temporary workaround to make sure the configuration happens
     every time this script is run. *)
  (try
    Sys.remove "_build/default/src/flags.sexp";
  with _ -> ());
  exit (Sys.command "dune build @configure --release")