PQescapeBytea is not multibyte aware

PQescapebytea() is not multibyte aware and will produce bad multibyte
character sequences. Example:

INSERT INTO t1(bytea_col) VALUES('characters produced by
PQescapebytea');
ERROR: Invalid EUC_JP character sequence found (0x8950)

I think 0x89 should be converted to '\\211' since 0x89 of 0x8950 is
considered as "non printable characters".

Any objection?
--
Tatsuo Ishii