Make XLogReaderInvalReadState static

This function is only used by xlogreader.c itself, so there's no need to
export it.  It was introduced by commit 3b02ea4f07 with the apparent
intention that it could be used externally, but I couldn't find any
external code calling it.

I (Álvaro) couldn't resist the urge to sort nearby function prototypes
properly while at it.

Author: Antonin Houska
Discussion: https://postgr.es/m/14984.1554998742@spoje.net

src/backend/access/transam/xlogreader.c

@@ -30,16 +30,17 @@
 #include "utils/memutils.h"
 #endif
 
-static bool allocate_recordbuf(XLogReaderState *state, uint32 reclength);
 
+static void report_invalid_record(XLogReaderState *state, const char *fmt,...)
+			pg_attribute_printf(2, 3);
+static bool allocate_recordbuf(XLogReaderState *state, uint32 reclength);
+static int	ReadPageInternal(XLogReaderState *state, XLogRecPtr pageptr,
+							 int reqLen);
+static void XLogReaderInvalReadState(XLogReaderState *state);
 static bool ValidXLogRecordHeader(XLogReaderState *state, XLogRecPtr RecPtr,
 								  XLogRecPtr PrevRecPtr, XLogRecord *record, bool randAccess);
 static bool ValidXLogRecord(XLogReaderState *state, XLogRecord *record,
 							XLogRecPtr recptr);
-static int	ReadPageInternal(XLogReaderState *state, XLogRecPtr pageptr,
-							 int reqLen);
-static void report_invalid_record(XLogReaderState *state, const char *fmt,...) pg_attribute_printf(2, 3);
-
 static void ResetDecoder(XLogReaderState *state);
 
 /* size of the buffer allocated for error message. */
@@ -621,7 +622,7 @@ err:
 /*
  * Invalidate the xlogreader's read state to force a re-read.
  */
-void
+static void
 XLogReaderInvalReadState(XLogReaderState *state)
 {
 	state->readSegNo = 0;

src/include/access/xlogreader.h

@@ -216,13 +216,9 @@ extern struct XLogRecord *XLogReadRecord(XLogReaderState *state,
 extern bool XLogReaderValidatePageHeader(XLogReaderState *state,
 										 XLogRecPtr recptr, char *phdr);
 
-/* Invalidate read state */
-extern void XLogReaderInvalReadState(XLogReaderState *state);
-
 #ifdef FRONTEND
 extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr);
 #endif							/* FRONTEND */
-
 /* Functions for decoding an XLogRecord */
 
 extern bool DecodeXLogRecord(XLogReaderState *state, XLogRecord *record,