let caml_sys_getenv: string => string;
let caml_sys_time: unit => float;
let os_type: unit => string;
let caml_sys_system_command: string => int;
let caml_sys_getcwd: unit => string;
let caml_sys_executable_name: unit => string;
let caml_sys_argv: unit => (string, array(string));
let caml_sys_exit: int => unit;
let caml_sys_is_directory: string => bool;
let caml_sys_file_exists: string => bool;