pgsql: Add bms_next_member(), and use it where appropriate.

Add bms_next_member(), and use it where appropriate.

This patch adds a way of iterating through the members of a bitmapset
nondestructively, unlike the old way with bms_first_member(). While
bms_next_member() is very slightly slower than bms_first_member()
(at least for typical-size bitmapsets), eliminating the need to palloc
and pfree a temporary copy of the target bitmapset is a significant win.
So this method should be preferred in all cases where a temporary copy
would be necessary.

Tom Lane, with suggestions from Dean Rasheed and David Rowley

Branch
------
master

Details
-------
http://git.postgresql.org/pg/commitdiff/f4e031c662a6b600b786c4849968a099c58fcce7

Modified Files
--------------
contrib/postgres_fdw/postgres_fdw.c | 14 ++++---
contrib/sepgsql/dml.c | 16 ++++----
src/backend/executor/execMain.c | 29 +++++++-------
src/backend/nodes/bitmapset.c | 68 ++++++++++++++++++++++++++++++---
src/backend/nodes/outfuncs.c | 6 +--
src/backend/optimizer/path/allpaths.c | 6 +--
src/backend/optimizer/path/indxpath.c | 6 +--
src/backend/optimizer/util/joininfo.c | 12 ++----
src/backend/optimizer/util/var.c | 6 +--
src/backend/rewrite/rewriteHandler.c | 8 ++--
src/backend/rewrite/rewriteManip.c | 6 +--
src/include/nodes/bitmapset.h | 1 +
src/pl/plpgsql/src/pl_exec.c | 12 ++----
13 files changed, 114 insertions(+), 76 deletions(-)