Cleanup of code for creating index entries. Functional indexes with

pass-by-ref data types --- eg, an index on lower(textfield) --- no longer
leak memory during index creation or update.  Clean up a lot of redundant
code ... did you know that copy, vacuum, truncate, reindex, extend index,
and bootstrap each basically duplicated the main executor's logic for
extracting information about an index and preparing index entries?
Functional indexes should be a little faster now too, due to removal
of repeated function lookups.
CREATE INDEX 'opt_type' clause is deimplemented by these changes,
but I haven't removed it from the parser yet (need to merge with
Thomas' latest change set first).

src/include/access/genam.h

@@ -7,14 +7,13 @@
  * Portions Copyright (c) 1996-2000, PostgreSQL, Inc
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: genam.h,v 1.23 2000/01/26 05:57:50 momjian Exp $
+ * $Id: genam.h,v 1.24 2000/07/14 22:17:53 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
 #ifndef GENAM_H
 #define GENAM_H
 
-#include "access/funcindex.h"
 #include "access/itup.h"
 #include "access/relscan.h"
 #include "access/sdir.h"
@@ -42,9 +41,6 @@ extern RetrieveIndexResult index_getnext(IndexScanDesc scan,
 extern RegProcedure index_cost_estimator(Relation relation);
 extern RegProcedure index_getprocid(Relation irel, AttrNumber attnum,
 				uint16 procnum);
-extern Datum GetIndexValue(HeapTuple tuple, TupleDesc hTupDesc,
-			  int attOff, AttrNumber *attrNums, FuncIndexInfo *fInfo,
-			  bool *attNull);
 
 /* in genam.c */
 extern IndexScanDesc RelationGetIndexScan(Relation relation, bool scanFromEnd,