Fix build on 1.9

use ffi;

use std::fmt;

use std::ptr;

use libc::{c_int, c_void, c_char};

use libc::{c_int, c_void, c_char, c_ulong};

use bn::{BigNum, BigNumRef};

use bio::{MemBio, MemBioSlice};

        unsafe {

            let rsa = try_ssl_null!(ffi::RSA_new());

            let rsa = RSA(rsa);

            let e = try!(BigNum::new_from(ffi::RSA_F4 as _));

            let e = try!(BigNum::new_from(ffi::RSA_F4 as c_ulong));

            try_ssl!(ffi::RSA_generate_key_ex(rsa.0, bits as c_int, e.raw(), ptr::null_mut()));