How to import C enum into Rust?

memcached.rs

// Rust code

use std::libc;
use std::ptr;

struct memcached_st;
struct memcached_server_st;
struct memcached_server_list_st;
type in_port_t = i32;
#[repr(C)]
type memcached_return_t = i32;

#[link(name = "memcached")]
extern {
    fn memcached_create(ptr: *memcached_st) -> *memcached_st;

    fn memcached_server_list_append(list: *memcached_server_list_st,
                                    hostname: *libc::c_char,
                                    port: in_port_t,
                                    error: *memcached_return_t) -> memcached_server_list_st;
}

fn main() {
    unsafe {
        let memc = memcached_create(ptr::null());
        println!("{:?}", memc);

        let rc: memcached_return_t = 0;
        let servers = memcached_server_list_append(ptr::null(), "127.0.0.1".to_c_str().unwrap(),
                                                   11211, &rc);
        println!("{:?}", servers);

        if rc == MEMCACHED_SUCCESS {  // error => no idea what you're talking about'
            println("Connected to server");
        } else {
            println("Connection failed");
        }
    }
}



//////////////////////////////////////////
//////////////////////////////////////////

// from libmemcached C code (return.h)
enum memcached_return_t {
  MEMCACHED_SUCCESS,
  MEMCACHED_FAILURE,
  MEMCACHED_HOST_LOOKUP_FAILURE, // getaddrinfo() and getnameinfo() only
  MEMCACHED_CONNECTION_FAILURE,
  MEMCACHED_CONNECTION_BIND_FAILURE,  // DEPRECATED, see MEMCACHED_HOST_LOOKUP_FAILURE
  MEMCACHED_WRITE_FAILURE,
  MEMCACHED_READ_FAILURE,
  MEMCACHED_UNKNOWN_READ_FAILURE,
  MEMCACHED_PROTOCOL_ERROR,
  MEMCACHED_CLIENT_ERROR,
  MEMCACHED_SERVER_ERROR, // Server returns "SERVER_ERROR"
  MEMCACHED_ERROR, // Server returns "ERROR"
  MEMCACHED_DATA_EXISTS,
  MEMCACHED_DATA_DOES_NOT_EXIST,
  MEMCACHED_NOTSTORED,
  MEMCACHED_STORED,
  MEMCACHED_NOTFOUND,
  MEMCACHED_MEMORY_ALLOCATION_FAILURE,
  MEMCACHED_PARTIAL_READ,
  MEMCACHED_SOME_ERRORS,
  MEMCACHED_NO_SERVERS,
  MEMCACHED_END,
  MEMCACHED_DELETED,
  MEMCACHED_VALUE,
  MEMCACHED_STAT,
  MEMCACHED_ITEM,
  MEMCACHED_ERRNO,
  MEMCACHED_FAIL_UNIX_SOCKET, // DEPRECATED
  MEMCACHED_NOT_SUPPORTED,
  MEMCACHED_NO_KEY_PROVIDED, /* Deprecated. Use MEMCACHED_BAD_KEY_PROVIDED! */
  MEMCACHED_FETCH_NOTFINISHED,
  MEMCACHED_TIMEOUT,
  MEMCACHED_BUFFERED,
  MEMCACHED_BAD_KEY_PROVIDED,
  MEMCACHED_INVALID_HOST_PROTOCOL,
  MEMCACHED_SERVER_MARKED_DEAD,
  MEMCACHED_UNKNOWN_STAT_KEY,
  MEMCACHED_E2BIG,
  MEMCACHED_INVALID_ARGUMENTS,
  MEMCACHED_KEY_TOO_BIG,
  MEMCACHED_AUTH_PROBLEM,
  MEMCACHED_AUTH_FAILURE,
  MEMCACHED_AUTH_CONTINUE,
  MEMCACHED_PARSE_ERROR,
  MEMCACHED_PARSE_USER_ERROR,
  MEMCACHED_DEPRECATED,
  MEMCACHED_IN_PROGRESS,
  MEMCACHED_SERVER_TEMPORARILY_DISABLED,
  MEMCACHED_SERVER_MEMORY_ALLOCATION_FAILURE,
  MEMCACHED_MAXIMUM_RETURN, /* Always add new error code before */
  MEMCACHED_CONNECTION_SOCKET_CREATE_FAILURE= MEMCACHED_ERROR
};