Function t4_t6_encode_set_encoding 

pub unsafe extern "C" fn t4_t6_encode_set_encoding(
    s: *mut t4_t6_encode_state_t,
    encoding: c_int,
) -> c_int

\brief Set the encoding for the encoded data. \param s The T.4/T.6 context. \param encoding The encoding. \return 0 for success, otherwise -1.