Compile and warning cleanup

src/backend/bootstrap/Makefile

src/backend/commands/define.c

src/backend/executor/execJunk.c

src/backend/executor/execTuples.c

src/backend/executor/nodeGroup.c

src/backend/executor/nodeNestloop.c

src/backend/executor/nodeSeqscan.c

src/backend/executor/nodeSort.c

src/backend/executor/nodeUnique.c

src/backend/libpq/pqcomm.c

src/backend/main/main.c

src/backend/nodes/copyfuncs.c

src/backend/nodes/equalfuncs.c

src/backend/nodes/outfuncs.c

src/backend/nodes/read.c

src/backend/nodes/readfuncs.c

src/backend/optimizer/path/allpaths.c

src/backend/optimizer/path/indxpath.c

src/backend/optimizer/path/prune.c

src/backend/optimizer/plan/createplan.c