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(-)