Function mbedtls_oid_get_oid_by_sig_alg 

pub unsafe extern "C" fn mbedtls_oid_get_oid_by_sig_alg(
    pk_alg: mbedtls_pk_type_t,
    md_alg: mbedtls_md_type_t,
    oid: *mut *const c_char,
    olen: *mut usize,
) -> c_int

\brief Translate md_type and pk_type into SignatureAlgorithm OID

\param md_alg message digest algorithm \param pk_alg public key algorithm \param oid place to store ASN.1 OID string pointer \param olen length of the OID

\return 0 if successful, or MBEDTLS_ERR_OID_NOT_FOUND