Merge branch 'master' into fdw_select_simple

diff --cc src/backend/nodes/copyfuncs.c
Simple merge

diff --cc src/backend/nodes/equalfuncs.c
Simple merge

diff --cc src/backend/nodes/outfuncs.c
Simple merge

diff --cc src/backend/optimizer/plan/createplan.c
Simple merge

diff --cc src/backend/optimizer/prep/prepunion.c
Simple merge

diff --cc src/include/nodes/nodes.h
Simple merge

diff --cc src/include/nodes/relation.h
Simple merge