Function BN_generate_prime

pub unsafe extern "C" fn BN_generate_prime(
    ret: *mut bignum_st,
    bits: i32,
    safe: i32,
    add: *const bignum_st,
    rem: *const bignum_st,
    callback: Option<unsafe extern "C" fn(_: i32, _: i32, _: *mut c_void)>,
    cb_arg: *mut c_void,
) -> *mut bignum_st