[postgis-users] GIST indexing update for PGQL 7.2

[Chris Hodgson]

I have committed the updates to support GIST indexing under PostgreSQL
7.2 +

Here is my change log:

- cut the gist indexing-related functions out of postgis_ops.c and put
them
 in postgis_gist.c, then put the new gist indexing functions for
 postgres >= 7.2 in the file postgis_gist_72

 - similarly, the sql definitions of the gist functions have been
 split into their own new sql.in file, with postgis_gist_72.sql.in
 containing the new postgres >= 7.2 definitions

 - the makefile has been updated to compile EITHER postgis_gist.c OR
 postgis_gist_72.c, and also to process EITHER postgis_gist.sql.in
 OR postgis_gist_72.sql and add the output to the end of postgis.sql

 - in order to compile the gist functions for posgres 7.2 or newer,
 make sure to point your PGSQL_SRC at the new source directory, and
 uncomment the line in the makefile which says PG72 = 1 (near the
 top)

 - some functions that were previously in postgis_ops.c were moved
 to postgis_fn.c, as part of a general cleanup I did when splitting
 off the gist functions into their own file

 - some definitions that were previously in postgis.h
 (unnecessarily) where removed, as they varied depending on which
 version of postgis_gist was being used

 - also edited the loader/Makefile to clean up properly