pgsql: Add NOWAIT option to SELECT FOR UPDATE/SHARE.

Log Message:
-----------
Add NOWAIT option to SELECT FOR UPDATE/SHARE.
Original patch by Hans-Juergen Schoenig, revisions by Karel Zak
and Tom Lane.

Modified Files:
--------------
    pgsql/doc/src/sgml/ref:
        select.sgml (r1.88 -> r1.89)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/select.sgml.diff?r1=1.88&r2=1.89)
        select_into.sgml (r1.35 -> r1.36)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/select_into.sgml.diff?r1=1.35&r2=1.36)
    pgsql/doc/src/sgml:
        sql.sgml (r1.37 -> r1.38)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/sql.sgml.diff?r1=1.37&r2=1.38)
    pgsql/src/backend/access/heap:
        heapam.c (r1.195 -> r1.196)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/access/heap/heapam.c.diff?r1=1.195&r2=1.196)
    pgsql/src/backend/access/transam:
        multixact.c (r1.5 -> r1.6)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/access/transam/multixact.c.diff?r1=1.5&r2=1.6)
    pgsql/src/backend/commands:
        trigger.c (r1.189 -> r1.190)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/commands/trigger.c.diff?r1=1.189&r2=1.190)
    pgsql/src/backend/executor:
        execMain.c (r1.251 -> r1.252)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/executor/execMain.c.diff?r1=1.251&r2=1.252)
        execUtils.c (r1.124 -> r1.125)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/executor/execUtils.c.diff?r1=1.124&r2=1.125)
    pgsql/src/backend/nodes:
        copyfuncs.c (r1.314 -> r1.315)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/nodes/copyfuncs.c.diff?r1=1.314&r2=1.315)
        equalfuncs.c (r1.251 -> r1.252)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/nodes/equalfuncs.c.diff?r1=1.251&r2=1.252)
        outfuncs.c (r1.258 -> r1.259)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/nodes/outfuncs.c.diff?r1=1.258&r2=1.259)
        readfuncs.c (r1.180 -> r1.181)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/nodes/readfuncs.c.diff?r1=1.180&r2=1.181)
    pgsql/src/backend/optimizer/prep:
        prepjointree.c (r1.29 -> r1.30)

(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/optimizer/prep/prepjointree.c.diff?r1=1.29&r2=1.30)
    pgsql/src/backend/parser:
        analyze.c (r1.323 -> r1.324)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/parser/analyze.c.diff?r1=1.323&r2=1.324)
        gram.y (r2.506 -> r2.507)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/parser/gram.y.diff?r1=2.506&r2=2.507)
        parse_relation.c (r1.112 -> r1.113)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/parser/parse_relation.c.diff?r1=1.112&r2=1.113)
        parse_type.c (r1.75 -> r1.76)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/parser/parse_type.c.diff?r1=1.75&r2=1.76)
    pgsql/src/backend/rewrite:
        rewriteHandler.c (r1.156 -> r1.157)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/rewrite/rewriteHandler.c.diff?r1=1.156&r2=1.157)
    pgsql/src/backend/storage/lmgr:
        lmgr.c (r1.77 -> r1.78)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/storage/lmgr/lmgr.c.diff?r1=1.77&r2=1.78)
    pgsql/src/backend/utils/adt:
        ruleutils.c (r1.204 -> r1.205)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/ruleutils.c.diff?r1=1.204&r2=1.205)
    pgsql/src/include/access:
        heapam.h (r1.102 -> r1.103)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/access/heapam.h.diff?r1=1.102&r2=1.103)
        multixact.h (r1.3 -> r1.4)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/access/multixact.h.diff?r1=1.3&r2=1.4)
    pgsql/src/include/catalog:
        catversion.h (r1.294 -> r1.295)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/catalog/catversion.h.diff?r1=1.294&r2=1.295)
    pgsql/src/include/nodes:
        execnodes.h (r1.136 -> r1.137)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/nodes/execnodes.h.diff?r1=1.136&r2=1.137)
        nodes.h (r1.174 -> r1.175)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/nodes/nodes.h.diff?r1=1.174&r2=1.175)
        parsenodes.h (r1.288 -> r1.289)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/nodes/parsenodes.h.diff?r1=1.288&r2=1.289)
    pgsql/src/include/parser:
        parse_node.h (r1.44 -> r1.45)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/parser/parse_node.h.diff?r1=1.44&r2=1.45)
    pgsql/src/include/storage:
        lmgr.h (r1.50 -> r1.51)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/storage/lmgr.h.diff?r1=1.50&r2=1.51)