pgsql: Create an SP-GiST opclass for inet/cidr.

Create an SP-GiST opclass for inet/cidr.

This seems to offer significantly better search performance than the
existing GiST opclass for inet/cidr, at least on data with a wide mix
of network mask lengths.  (That may suggest that the data splitting
heuristics in the GiST opclass could be improved.)

Emre Hasegeli, with mostly-cosmetic adjustments by me

Discussion: <CAE2gYzxtth9qatW_OAqdOjykS0bxq7AYHLuyAQLPgT7H9ZU0Cw@mail.gmail.com>

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/77e2906821e2aec3c0807866a84c2934feeac8be

Modified Files
--------------
doc/src/sgml/spgist.sgml                 |  17 +
src/backend/utils/adt/Makefile           |   2 +-
src/backend/utils/adt/network_spgist.c   | 708 +++++++++++++++++++++++++++++++
src/include/catalog/catversion.h         |   2 +-
src/include/catalog/pg_amop.h            |  15 +
src/include/catalog/pg_amproc.h          |   5 +
src/include/catalog/pg_opclass.h         |   1 +
src/include/catalog/pg_opfamily.h        |   1 +
src/include/catalog/pg_proc.h            |  12 +
src/include/utils/inet.h                 |   9 +
src/test/regress/expected/inet.out       | 148 +++++++
src/test/regress/expected/opr_sanity.out |  11 +-
src/test/regress/sql/inet.sql            |  23 +
13 files changed, 951 insertions(+), 3 deletions(-)