pgsql: Add strlcat() from OpenBSD, to be used for replacing strncat and

Log Message:
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Add strlcat() from OpenBSD, to be used for replacing strncat and other
strange coding practices.

Modified Files:
--------------
    pgsql:
        configure (r1.533 -> r1.534)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/configure.diff?r1=1.533&r2=1.534)
        configure.in (r1.500 -> r1.501)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/configure.in.diff?r1=1.500&r2=1.501)
    pgsql/src/bin/pg_config:
        pg_config.c (r1.23 -> r1.24)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/bin/pg_config/pg_config.c.diff?r1=1.23&r2=1.24)
    pgsql/src/include:
        pg_config.h.in (r1.110 -> r1.111)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/pg_config.h.in.diff?r1=1.110&r2=1.111)
        port.h (r1.109 -> r1.110)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/port.h.diff?r1=1.109&r2=1.110)

Added Files:
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    pgsql/src/port:
        strlcat.c (r1.1)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/port/strlcat.c?rev=1.1&content-type=text/x-cvsweb-markup)