Обсуждение: pgsql: This patch makes some cleanups to contrib/ to silence some sparse

Log Message:
-----------
This patch makes some cleanups to contrib/ to silence some sparse
warnings:

- remove pointless "extern" keyword from some function definitions in
contrib/tsearch2

- use "NULL" not "0" as NULL pointer in contrib/tsearch,
contrib/tsearch2, contrib/pgbench, and contrib/vacuumlo

Modified Files:
--------------
    pgsql/contrib/pgbench:
        pgbench.c (r1.34 -> r1.35)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/pgbench/pgbench.c.diff?r1=1.34&r2=1.35)
    pgsql/contrib/tsearch:
        query.c (r1.15 -> r1.16)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/tsearch/query.c.diff?r1=1.15&r2=1.16)
    pgsql/contrib/tsearch2:
        query.c (r1.10 -> r1.11)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/tsearch2/query.c.diff?r1=1.10&r2=1.11)
    pgsql/contrib/tsearch2/snowball:
        api.c (r1.4 -> r1.5)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/tsearch2/snowball/api.c.diff?r1=1.4&r2=1.5)
        utilities.c (r1.4 -> r1.5)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/tsearch2/snowball/utilities.c.diff?r1=1.4&r2=1.5)
    pgsql/contrib/vacuumlo:
        vacuumlo.c (r1.27 -> r1.28)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/vacuumlo/vacuumlo.c.diff?r1=1.27&r2=1.28)