The following macros are now defined for openssl < 1.1 so that we can remove the code performing direct access to the structures : BIO_get_data(), BIO_set_data(), BIO_set_init(), BIO_meth_free(), BIO_meth_new(), BIO_meth_set_gets(), BIO_meth_set_puts(), BIO_meth_set_read(), BIO_meth_set_write(), BIO_meth_set_create(), BIO_meth_set_ctrl(), BIO_meth_set_destroy()