pgsql: Improve the representation of FOR UPDATE/FOR SHARE so that we can

Log Message:
-----------
Improve the representation of FOR UPDATE/FOR SHARE so that we can
support both FOR UPDATE and FOR SHARE in one command, as well as both
NOWAIT and normal WAIT behavior. The more general code is actually
simpler and cleaner.

Modified Files:
--------------
pgsql/doc/src/sgml/ref:
select.sgml (r1.90 -> r1.91)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/select.sgml.diff?r1=1.90&r2=1.91)
select_into.sgml (r1.36 -> r1.37)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/select_into.sgml.diff?r1=1.36&r2=1.37)
pgsql/doc/src/sgml:
sql.sgml (r1.39 -> r1.40)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/sql.sgml.diff?r1=1.39&r2=1.40)
pgsql/src/backend/executor:
execMain.c (r1.269 -> r1.270)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/executor/execMain.c.diff?r1=1.269&r2=1.270)
execUtils.c (r1.133 -> r1.134)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/executor/execUtils.c.diff?r1=1.133&r2=1.134)
pgsql/src/backend/nodes:
copyfuncs.c (r1.334 -> r1.335)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/nodes/copyfuncs.c.diff?r1=1.334&r2=1.335)
equalfuncs.c (r1.270 -> r1.271)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/nodes/equalfuncs.c.diff?r1=1.270&r2=1.271)
outfuncs.c (r1.273 -> r1.274)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/nodes/outfuncs.c.diff?r1=1.273&r2=1.274)
readfuncs.c (r1.188 -> r1.189)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/nodes/readfuncs.c.diff?r1=1.188&r2=1.189)
pgsql/src/backend/optimizer/path:
allpaths.c (r1.144 -> r1.145)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/optimizer/path/allpaths.c.diff?r1=1.144&r2=1.145)
pgsql/src/backend/optimizer/plan:
createplan.c (r1.209 -> r1.210)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/optimizer/plan/createplan.c.diff?r1=1.209&r2=1.210)
pgsql/src/backend/optimizer/prep:
prepjointree.c (r1.37 -> r1.38)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/optimizer/prep/prepjointree.c.diff?r1=1.37&r2=1.38)
preptlist.c (r1.81 -> r1.82)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/optimizer/prep/preptlist.c.diff?r1=1.81&r2=1.82)
prepunion.c (r1.131 -> r1.132)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/optimizer/prep/prepunion.c.diff?r1=1.131&r2=1.132)
pgsql/src/backend/parser:
analyze.c (r1.333 -> r1.334)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/parser/analyze.c.diff?r1=1.333&r2=1.334)
gram.y (r2.543 -> r2.544)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/parser/gram.y.diff?r1=2.543&r2=2.544)
parse_relation.c (r1.122 -> r1.123)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/parser/parse_relation.c.diff?r1=1.122&r2=1.123)
parse_type.c (r1.80 -> r1.81)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/parser/parse_type.c.diff?r1=1.80&r2=1.81)
pgsql/src/backend/rewrite:
rewriteHandler.c (r1.162 -> r1.163)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/rewrite/rewriteHandler.c.diff?r1=1.162&r2=1.163)
rewriteManip.c (r1.98 -> r1.99)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/rewrite/rewriteManip.c.diff?r1=1.98&r2=1.99)
pgsql/src/backend/tcop:
utility.c (r1.256 -> r1.257)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/tcop/utility.c.diff?r1=1.256&r2=1.257)
pgsql/src/backend/utils/adt:
ruleutils.c (r1.220 -> r1.221)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/ruleutils.c.diff?r1=1.220&r2=1.221)
pgsql/src/include/catalog:
catversion.h (r1.327 -> r1.328)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/catalog/catversion.h.diff?r1=1.327&r2=1.328)
pgsql/src/include/nodes:
execnodes.h (r1.149 -> r1.150)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/nodes/execnodes.h.diff?r1=1.149&r2=1.150)
nodes.h (r1.185 -> r1.186)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/nodes/nodes.h.diff?r1=1.185&r2=1.186)
parsenodes.h (r1.309 -> r1.310)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/nodes/parsenodes.h.diff?r1=1.309&r2=1.310)
pgsql/src/include/parser:
analyze.h (r1.32 -> r1.33)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/parser/analyze.h.diff?r1=1.32&r2=1.33)
parse_node.h (r1.48 -> r1.49)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/parser/parse_node.h.diff?r1=1.48&r2=1.49)
parsetree.h (r1.32 -> r1.33)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/parser/parsetree.h.diff?r1=1.32&r2=1.33)