DECLARE_PEM_rw_cb_attr
DECLARE_PEM_rw_cb_attr(extern, name, type)
DECLARE_PEM_rw_cb_attr(OSSL_DEPRECATEDIN_3_0, RSAPrivateKey, RSA)
DECLARE_PEM_rw_cb_attr(OSSL_DEPRECATEDIN_3_0, DSAPrivateKey, DSA)
DECLARE_PEM_rw_cb_attr(OSSL_DEPRECATEDIN_3_0, ECPrivateKey, EC_KEY)