Fix segment argument for smgr slru download functions.

In PG17+ that should be int64, even if it may or may not yet be used for
neon-relevant segments.

Author: Matthias van de Meent

src/backend/access/transam/slru.c

@@ -736,10 +736,10 @@ SlruInternalWritePage(SlruCtl ctl, int slotno, SlruWriteAll fdata)
  *   ereports if some other error happened
  */
 static bool
-SimpleLruDownloadSegment(SlruCtl ctl, int pageno, char const *path)
+SimpleLruDownloadSegment(SlruCtl ctl, int64 pageno, char const *path)
 {
 	SlruShared	shared = ctl->shared;
-	int			segno;
+	int64		segno;
 
 	/* If page is greater than latest written page, then do not try to download segment from server */
 	if (ctl->PagePrecedes(pg_atomic_read_u64(&shared->latest_page_number), pageno))

src/backend/storage/smgr/smgr.c

@@ -1106,7 +1106,7 @@ smgr_end_unlogged_build(SMgrRelation reln)
  * file and returns 'true'. If the file is not found, returns 'false'.
  */
 bool
-smgr_read_slru_segment(const char *path, int segno)
+smgr_read_slru_segment(const char *path, int64 segno)
 {
 	if (read_slru_segment_hook)
 		return read_slru_segment_hook(path, segno);

src/include/storage/smgr.h

@@ -155,7 +155,7 @@ extern finish_unlogged_build_phase_1_hook_type finish_unlogged_build_phase_1_hoo
 extern end_unlogged_build_hook_type end_unlogged_build_hook;
 
 /* NEON: Hook for reading an SLRU segment from e.g. remote storage */
-typedef bool (*read_slru_segment_hook_type) (const char *path, int segno);
+typedef bool (*read_slru_segment_hook_type) (const char *path, int64 segno);
 extern read_slru_segment_hook_type read_slru_segment_hook;
 
 /* NEON: Alternative implementation of calculate_database_size(), to make it O(1) */
@@ -217,7 +217,7 @@ extern void	smgr_finish_unlogged_build_phase_1(SMgrRelation reln);
 extern void smgr_end_unlogged_build(SMgrRelation reln);
 
 /* Neon: Allow on-demand download of SLRU segment data */
-extern bool smgr_read_slru_segment(const char *path, int segno);
+extern bool smgr_read_slru_segment(const char *path, int64 segno);
 
 static inline void
 smgrread(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,