pgsql: Standardize on using the Min, Max, and Abs macros that are in our

Log Message:
-----------
Standardize on using the Min, Max, and Abs macros that are in our c.h file,
getting rid of numerous ad-hoc versions that have popped up in various
places.  Shortens code and avoids conflict with Windows min() and max()
macros.

Modified Files:
--------------
    pgsql/contrib/cube:
        cube.c (r1.17 -> r1.18)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/cube/cube.c.diff?r1=1.17&r2=1.18)
    pgsql/contrib/intarray:
        _int.h (r1.3 -> r1.4)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/intarray/_int.h.diff?r1=1.3&r2=1.4)
        _int_gist.c (r1.4 -> r1.5)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/intarray/_int_gist.c.diff?r1=1.4&r2=1.5)
        _int_tool.c (r1.2 -> r1.3)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/intarray/_int_tool.c.diff?r1=1.2&r2=1.3)
        _intbig_gist.c (r1.4 -> r1.5)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/intarray/_intbig_gist.c.diff?r1=1.4&r2=1.5)
    pgsql/contrib/ltree:
        _ltree_gist.c (r1.9 -> r1.10)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/ltree/_ltree_gist.c.diff?r1=1.9&r2=1.10)
        ltree.h (r1.9 -> r1.10)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/ltree/ltree.h.diff?r1=1.9&r2=1.10)
        ltree_gist.c (r1.7 -> r1.8)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/ltree/ltree_gist.c.diff?r1=1.7&r2=1.8)
        ltree_op.c (r1.7 -> r1.8)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/ltree/ltree_op.c.diff?r1=1.7&r2=1.8)
    pgsql/contrib/miscutil:
        misc_utils.c (r1.17 -> r1.18)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/miscutil/misc_utils.c.diff?r1=1.17&r2=1.18)
        misc_utils.h (r1.11 -> r1.12)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/miscutil/misc_utils.h.diff?r1=1.11&r2=1.12)
        misc_utils.sql.in (r1.6 -> r1.7)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/miscutil/misc_utils.sql.in.diff?r1=1.6&r2=1.7)
    pgsql/contrib/seg:
        seg.c (r1.11 -> r1.12)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/seg/seg.c.diff?r1=1.11&r2=1.12)
    pgsql/contrib/string:
        string_io.c (r1.18 -> r1.19)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/string/string_io.c.diff?r1=1.18&r2=1.19)
    pgsql/contrib/tsearch:
        gistidx.c (r1.7 -> r1.8)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/tsearch/gistidx.c.diff?r1=1.7&r2=1.8)
        gistidx.h (r1.5 -> r1.6)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/tsearch/gistidx.h.diff?r1=1.5&r2=1.6)
    pgsql/contrib/tsearch2:
        gistidx.c (r1.4 -> r1.5)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/tsearch2/gistidx.c.diff?r1=1.4&r2=1.5)
        gistidx.h (r1.1 -> r1.2)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/tsearch2/gistidx.h.diff?r1=1.1&r2=1.2)
        rank.c (r1.4 -> r1.5)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/tsearch2/rank.c.diff?r1=1.4&r2=1.5)
    pgsql/src/backend/postmaster:
        postmaster.c (r1.434 -> r1.435)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/postmaster/postmaster.c.diff?r1=1.434&r2=1.435)
    pgsql/src/interfaces/libpq:
        fe-exec.c (r1.164 -> r1.165)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/libpq/fe-exec.c.diff?r1=1.164&r2=1.165)
    pgsql/src/test/regress:
        regress.c (r1.61 -> r1.62)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/regress.c.diff?r1=1.61&r2=1.62)