diff --git a/src/backend/storage/sync/sync.c b/src/backend/storage/sync/sync.c
index 768d1dbfc41..04fcb06056d 100644
--- a/src/backend/storage/sync/sync.c
+++ b/src/backend/storage/sync/sync.c
@@ -37,8 +37,6 @@
 #include "utils/inval.h"
 #include "utils/memutils.h"
 
-static MemoryContext pendingOpsCxt; /* context for the pending ops state  */
-
 /*
  * In some contexts (currently, standalone backends and the checkpointer)
  * we keep track of pending fsync operations: we need to remember all relation
diff --git a/src/backend/utils/misc/guc_tables.c b/src/backend/utils/misc/guc_tables.c
index 4665b0a35c3..71e27f8eb05 100644
--- a/src/backend/utils/misc/guc_tables.c
+++ b/src/backend/utils/misc/guc_tables.c
@@ -97,7 +97,6 @@ extern char *default_tablespace;
 extern char *temp_tablespaces;
 extern bool ignore_checksum_failure;
 extern bool ignore_invalid_pages;
-extern bool synchronize_seqscans;
 
 #ifdef TRACE_SYNCSCAN
 extern bool trace_syncscan;
@@ -530,8 +529,6 @@ char	   *HbaFileName;
 char	   *IdentFileName;
 char	   *external_pid_file;
 
-char	   *pgstat_temp_directory;
-
 char	   *application_name;
 
 int			tcp_keepalives_idle;
diff --git a/src/include/libpq/auth.h b/src/include/libpq/auth.h
index 3b3b2cc4aaa..7fac05b813f 100644
--- a/src/include/libpq/auth.h
+++ b/src/include/libpq/auth.h
@@ -19,7 +19,6 @@
 extern PGDLLIMPORT char *pg_krb_server_keyfile;
 extern PGDLLIMPORT bool pg_krb_caseins_users;
 extern PGDLLIMPORT bool pg_gss_accept_delegation;
-extern PGDLLIMPORT char *pg_krb_realm;
 
 extern void ClientAuthentication(Port *port);
 extern void sendAuthRequest(Port *port, AuthRequest areq, const char *extradata,