Fix a bunch of functions that were declared static then defined not-static.

Per testing with a compiler that whines about this.

src/backend/access/transam/xlog.c

@@ -8318,7 +8318,7 @@ CreateCheckPoint(int flags)
  * CreateRestartPoint() allows for the case where recovery may end before
  * the restartpoint completes so there is no concern of concurrent behaviour.
  */
-void
+static void
 CreateEndOfRecoveryRecord(void)
 {
 	xl_end_of_recovery xlrec;

src/backend/replication/logical/reorderbuffer.c

@@ -322,7 +322,7 @@ ReorderBufferGetTXN(ReorderBuffer *rb)
  * Deallocation might be delayed for efficiency purposes, for details check
  * the comments above max_cached_changes's definition.
  */
-void
+static void
 ReorderBufferReturnTXN(ReorderBuffer *rb, ReorderBufferTXN *txn)
 {
 	/* clean the lookup cache if we were cached (quite likely) */

src/backend/utils/cache/relcache.c

@@ -2381,7 +2381,7 @@ RelationCloseSmgrByOid(Oid relationId)
 	RelationCloseSmgr(relation);
 }
 
-void
+static void
 RememberToFreeTupleDescAtEOX(TupleDesc td)
 {
 	if (EOXactTupleDescArray == NULL)

src/backend/utils/misc/guc.c

@@ -5340,7 +5340,7 @@ config_enum_get_options(struct config_enum * record, const char *prefix,
  *	1: the value is valid
  *	0: the name or value is invalid
  */
-bool
+static bool
 validate_conf_option(struct config_generic * record, const char *name,
 					 const char *value, GucSource source, int elevel,
 					 bool freemem, void *newval, void **newextra)

src/bin/pg_ctl/pg_ctl.c

@@ -399,7 +399,7 @@ readfile(const char *path)
 /*
  * Free memory allocated for optlines through readfile()
  */
-void
+static void
 free_readfile(char **optlines)
 {
 	char	   *curr_line = NULL;