Fixes from Janko Richter <jankorichter@yahoo.de>

- Fix wrong index results on text, char, varchar for multibyte strings
- Fix some SIGFPE signals
- Add support for infinite timestamps
- Because of locale settings, btree_gist can not be a prefix index anymore (for text).
  Each node holds now just the lower and upper boundary.

contrib/btree_gist/btree_utils_num.h

@@ -43,14 +43,24 @@ typedef struct
 */
 
 
-#define penalty_range_enlarge(olower,oupper,nlower,nupper) do { \
-  res = 0; \
-  if ( (nupper) > (oupper) ) \
-	res += ( (nupper) - (oupper) ); \
-  if (	(olower) > (nlower)  ) \
-	res += ( (olower) - (nlower) ); \
-} while (0);
 
+/*
+ * Note: The factor 0.49 in following macro avoids floating point overflows
+*/
+#define penalty_num(result,olower,oupper,nlower,nupper) do { \
+  double    tmp = 0.0F; \
+  (*(result))   = 0.0F; \
+  if ( (nupper) > (oupper) ) \
+	  tmp += ( ((double)nupper)*0.49F - ((double)oupper)*0.49F ); \
+  if (	(olower) > (nlower)  ) \
+	  tmp += ( ((double)olower)*0.49F - ((double)nlower)*0.49F ); \
+  if (tmp > 0.0F) \
+  { \
+    (*(result)) += FLT_MIN; \
+    (*(result)) += (float) ( ((double)(tmp)) / ( (double)(tmp) + ( ((double)(oupper))*0.49F - ((double)(olower))*0.49F ) ) ); \
+    (*(result)) *= (FLT_MAX / (((GISTENTRY *) PG_GETARG_POINTER(0))->rel->rd_att->natts + 1)); \
+  } \
+} while (0);
 
 
 extern bool gbt_num_consistent(const GBT_NUMKEY_R * key, const void *query,