OSSL_KDF_PARAM_KBKDF_USE_SEPARATOR
p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_KBKDF_USE_SEPARATOR);
OSSL_PARAM_int(OSSL_KDF_PARAM_KBKDF_USE_SEPARATOR, NULL),
*p++ = OSSL_PARAM_construct_int(OSSL_KDF_PARAM_KBKDF_USE_SEPARATOR,
*p++ = OSSL_PARAM_construct_int(OSSL_KDF_PARAM_KBKDF_USE_SEPARATOR, &sep);