heap_fetch requires buffer pointer, must be released; heap_getnext

no longer returns buffer pointer, can be gotten from scan;
	descriptor; bootstrap can create multi-key indexes;
pg_procname index now is multi-key index; oidint2, oidint4, oidname
are gone (must be removed from regression tests); use System Cache
rather than sequential scan in many places; heap_modifytuple no
longer takes buffer parameter; remove unused buffer parameter in
a few other functions; oid8 is not index-able; remove some use of
single-character variable names; cleanup Buffer variables usage
and scan descriptor looping; cleaned up allocation and freeing of
tuples; 18k lines of diff;

src/interfaces/ecpg/preproc/type.h

@@ -75,7 +75,7 @@ struct when
 	char	   	*str;
 };
 
-struct index
+struct RelationGetRelidindex
 {
     int index1;
     int index2;