pgsnmpd - pgsnmpd: Added beginnings of custom query handling.

Log Message:
-----------
Added beginnings of custom query handling. Also fixed compiler warnings and
8.4-ified pg_amop MIB (which will likely disappear in favor of information
schema soon enough anyway).

Modified Files:
--------------
pgsnmpd:
Makefile (r1.19 -> r1.20)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgsnmpd/pgsnmpd/Makefile?r1=1.19&r2=1.20)
pgsnmpd.c (r1.25 -> r1.26)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgsnmpd/pgsnmpd/pgsnmpd.c?r1=1.25&r2=1.26)
pgsnmpd/RDBMS-MIB_src/rdbmsSrvInfoTable:
rdbmsSrvInfoTable_data_access.c (r1.6 -> r1.7)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgsnmpd/pgsnmpd/RDBMS-MIB_src/rdbmsSrvInfoTable/rdbmsSrvInfoTable_data_access.c?r1=1.6&r2=1.7)
pgsnmpd/pgsql_mib_pieces:
PGSQL-MIB (r1.4 -> r1.5)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgsnmpd/pgsnmpd/pgsql_mib_pieces/PGSQL-MIB?r1=1.4&r2=1.5)
pg_amop.mib (r1.5 -> r1.6)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgsnmpd/pgsnmpd/pgsql_mib_pieces/pg_amop.mib?r1=1.5&r2=1.6)
pg_amop.tbldef (r1.4 -> r1.5)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgsnmpd/pgsnmpd/pgsql_mib_pieces/pg_amop.tbldef?r1=1.4&r2=1.5)

Added Files:
-----------
pgsnmpd:
customquery.c (r1.1)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgsnmpd/pgsnmpd/customquery.c?rev=1.1&content-type=text/x-cvsweb-markup)
customquery.h (r1.1)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgsnmpd/pgsnmpd/customquery.h?rev=1.1&content-type=text/x-cvsweb-markup)