Adjust the APIs for GIN opclass support functions to allow the extractQuery()

method to pass extra data to the consistent() and comparePartial() methods.
This is the core infrastructure needed to support the soon-to-appear
contrib/btree_gin module.  The APIs are still upward compatible with the
definitions used in 8.3 and before, although *not* with the previous 8.4devel
function definitions.

catversion bump for changes in pg_proc entries (although these are just
cosmetic, since GIN doesn't actually look at the function signature before
calling it...)

Teodor Sigaev and Oleg Bartunov

src/include/access/gin.h

@@ -4,7 +4,7 @@
  *
  *	Copyright (c) 2006-2009, PostgreSQL Global Development Group
  *
- *	$PostgreSQL: pgsql/src/include/access/gin.h,v 1.30 2009/03/24 22:06:03 tgl Exp $
+ *	$PostgreSQL: pgsql/src/include/access/gin.h,v 1.31 2009/03/25 22:19:01 tgl Exp $
  *--------------------------------------------------------------------------
  */
 #ifndef GIN_H
@@ -481,6 +481,7 @@ typedef struct GinScanEntryData
 	/* entry, got from extractQueryFn */
 	Datum		entry;
 	OffsetNumber	attnum;
+	Pointer			extra_data;
 
 	/* Current page in posting tree */
 	Buffer		buffer;
@@ -515,6 +516,7 @@ typedef struct GinScanKeyData
 
 	/* array of scans per entry */
 	GinScanEntry scanEntry;
+	Pointer		 *extra_data;
 
 	/* for calling consistentFn(GinScanKey->entryRes, strategy, query) */
 	StrategyNumber strategy;