Function openssl_sys::SSL_CTX_set_alpn_select_cb

pub unsafe extern fn SSL_CTX_set_alpn_select_cb(ssl: *mut SSL_CTX,
                                                cb: extern fn(_: *mut SSL, _: *mut *const c_uchar, _: *mut c_uchar, _: *const c_uchar, _: c_uint, _: *mut c_void) -> c_int,
                                                arg: *mut c_void)