It doesn't really need rel.h; relcache.h is enough.
#include "access/spgist_private.h"
#include "miscadmin.h"
#include "storage/bufmgr.h"
+#include "utils/rel.h"
/*
#include "storage/bufmgr.h"
#include "storage/smgr.h"
#include "utils/memutils.h"
+#include "utils/rel.h"
typedef struct
#include "storage/bufmgr.h"
#include "utils/datum.h"
#include "utils/memutils.h"
+#include "utils/rel.h"
typedef void (*storeRes_func) (SpGistScanOpaque so, ItemPointer heapPtr,
#include "access/itup.h"
#include "access/spgist.h"
#include "nodes/tidbitmap.h"
-#include "utils/rel.h"
+#include "storage/relfilenode.h"
+#include "utils/relcache.h"
/* Page numbers of fixed-location pages */