databases/postgresql91(-client): Fix build for gcc46 and gcc47

Postgresql91 uses non-constant array sizes in record definitions which
gcc enforces starting with 4.6.  These index sizes are defined as macros
using functions such as offsetof.  These patches introduce enums where
the macros become constant expressions which gcc 4.6+ will accept.

GCC 4.7 also introduces the unused-but-set-variable warning which is
popping up all over the place in pgsql91, so silence these warnings -
they are harmless and get optimized out anyway.

No revbump because functionality won't change on binaries generated with
gcc4.5 and below.


(marino)

$NetBSD: patch-src_backend_access_gist_gistutil.c,v 1.1 2012/10/07 10:24:54 marino Exp $

GCC 4.6 and GCC 4.7 do not consider the storage array has having a constant
size due to the macro definition of GEVHDRSZ found in gist.h
"gistutil.c:248:14: error: storage size of `storage` isn't constant"
Using an enumeration satisfies these compilers.

--- src/backend/access/gist/gistutil.c.orig	2012-09-19 21:50:31.000000000 +0000
+++ src/backend/access/gist/gistutil.c
@@ -244,8 +244,11 @@ gistMakeUnionKey(GISTSTATE *giststate, i
 {
 
 	int			dstsize;
+	enum {
+		GEV_STORAGE_SIZE = 2 * sizeof(GISTENTRY) + GEVHDRSZ
+	};
 
-	static char storage[2 * sizeof(GISTENTRY) + GEVHDRSZ];
+	static char storage[GEV_STORAGE_SIZE];
 	GistEntryVector *evec = (GistEntryVector *) storage;
 
 	evec->n = 2;

$NetBSD: patch-src_include_access_htup.h,v 1.1 2012/10/07 10:24:54 marino Exp $

Fixes GCC 4.7 warning and error
Also see comments about similar problems in patch-src_include_access_ihup.h
htup.h:464:2: warning: variably modified 'mt_padding' at file scope
       [enabled by default]
relscan.h:51:15: error: variably modified 'rs_vistuples' at file scope

The relscan.h error is caused by the MaxHeapTuplesPerPage definition found
in htup.h.  Use enum method to satisfy gcc.

--- src/include/access/htup.h.orig	2012-09-19 21:50:31.000000000 +0000
+++ src/include/access/htup.h
@@ -16,6 +16,7 @@
 
 #include "access/tupdesc.h"
 #include "access/tupmacs.h"
+#include "storage/bufpage.h"
 #include "storage/itemptr.h"
 #include "storage/relfilenode.h"
 
@@ -405,9 +406,10 @@ do { \
  * pointers to this anyway, to avoid excessive line-pointer bloat and not
  * require increases in the size of work arrays.
  */
-#define MaxHeapTuplesPerPage	\
-	((int) ((BLCKSZ - SizeOfPageHeaderData) / \
-			(MAXALIGN(offsetof(HeapTupleHeaderData, t_bits)) + sizeof(ItemIdData))))
+#define MaxHeapTuplesPerPageInt \
+	(BLCKSZ - SizeOfPageHeaderData) / \
+		(MAXALIGN(offsetof(HeapTupleHeaderData, t_bits)) + \
+		sizeof(ItemIdData))
 
 /*
  * MaxAttrSize is a somewhat arbitrary upper limit on the declared size of
@@ -452,11 +454,16 @@ do { \
  */
 #define MINIMAL_TUPLE_OFFSET \
 	((offsetof(HeapTupleHeaderData, t_infomask2) - sizeof(uint32)) / MAXIMUM_ALIGNOF * MAXIMUM_ALIGNOF)
-#define MINIMAL_TUPLE_PADDING \
+#define MINIMAL_TUPLE_PADDING_MACRO \
 	((offsetof(HeapTupleHeaderData, t_infomask2) - sizeof(uint32)) % MAXIMUM_ALIGNOF)
 #define MINIMAL_TUPLE_DATA_OFFSET \
 	offsetof(MinimalTupleData, t_infomask2)
 
+enum {
+	MINIMAL_TUPLE_PADDING = MINIMAL_TUPLE_PADDING_MACRO,
+	MaxHeapTuplesPerPage = MaxHeapTuplesPerPageInt
+};
+
 typedef struct MinimalTupleData
 {
 	uint32		t_len;			/* actual length of minimal tuple */

$NetBSD: patch-src_include_access_itup.h,v 1.1 2012/10/07 10:24:54 marino Exp $

GCC 4.7 fails on nbtree.h:509:16 with this message:
error: variably modified 'items' at file scope
It does like defining records with "variable" array lengths
Use the enum trick to convertMaxIndexTuplesPerPage into a constant

--- src/include/access/itup.h.orig	2012-09-19 21:50:31.000000000 +0000
+++ src/include/access/itup.h
@@ -133,10 +133,13 @@ typedef IndexAttributeBitMapData *IndexA
  * IndexTupleData struct.  We arrive at the divisor because each tuple
  * must be maxaligned, and it must have an associated item pointer.
  */
-#define MaxIndexTuplesPerPage	\
-	((int) ((BLCKSZ - SizeOfPageHeaderData) / \
-			(MAXALIGN(sizeof(IndexTupleData) + 1) + sizeof(ItemIdData))))
+#define MaxIndexTuplesPerPageInt \
+	(BLCKSZ - SizeOfPageHeaderData) / \
+                (MAXALIGN(sizeof(IndexTupleData) + 1) + sizeof(ItemIdData))
 
+enum {
+	MaxIndexTuplesPerPage = MaxIndexTuplesPerPageInt
+};
 
 /* routines in indextuple.c */
 extern IndexTuple index_form_tuple(TupleDesc tupleDescriptor,