diff --git a/src/include/libpq/oauth.h b/src/include/libpq/oauth.h
index 2c6892ffba4..3f4c9acd8b0 100644
--- a/src/include/libpq/oauth.h
+++ b/src/include/libpq/oauth.h
@@ -91,7 +91,7 @@ typedef const OAuthValidatorCallbacks *(*OAuthValidatorModuleInit) (void);
 extern PGDLLEXPORT const OAuthValidatorCallbacks *_PG_oauth_validator_module_init(void);
 
 /* Implementation */
-extern const pg_be_sasl_mech pg_be_oauth_mech;
+extern PGDLLIMPORT const pg_be_sasl_mech pg_be_oauth_mech;
 
 /*
  * Ensure a validator named in the HBA is permitted by the configuration.
diff --git a/src/include/postmaster/postmaster.h b/src/include/postmaster/postmaster.h
index 39566ee2bd5..92497cd6a0f 100644
--- a/src/include/postmaster/postmaster.h
+++ b/src/include/postmaster/postmaster.h
@@ -48,7 +48,7 @@ typedef struct
 } PMChild;
 
 #ifdef EXEC_BACKEND
-extern int	num_pmchild_slots;
+extern PGDLLIMPORT int num_pmchild_slots;
 #endif
 
 /* GUC options */
@@ -117,7 +117,7 @@ pg_noreturn extern void SubPostmasterMain(int argc, char *argv[]);
 #endif
 
 /* defined in pmchild.c */
-extern dlist_head ActiveChildList;
+extern PGDLLIMPORT dlist_head ActiveChildList;
 
 extern void InitPostmasterChildSlots(void);
 extern PMChild *AssignPostmasterChildSlot(BackendType btype);
diff --git a/src/include/storage/bufmgr.h b/src/include/storage/bufmgr.h
index 96150a6cfe9..33a8b8c06fb 100644
--- a/src/include/storage/bufmgr.h
+++ b/src/include/storage/bufmgr.h
@@ -173,8 +173,8 @@ extern PGDLLIMPORT int checkpoint_flush_after;
 extern PGDLLIMPORT int backend_flush_after;
 extern PGDLLIMPORT int bgwriter_flush_after;
 
-extern const PgAioHandleCallbacks aio_shared_buffer_readv_cb;
-extern const PgAioHandleCallbacks aio_local_buffer_readv_cb;
+extern PGDLLIMPORT const PgAioHandleCallbacks aio_shared_buffer_readv_cb;
+extern PGDLLIMPORT const PgAioHandleCallbacks aio_local_buffer_readv_cb;
 
 /* in buf_init.c */
 extern PGDLLIMPORT char *BufferBlocks;
diff --git a/src/include/storage/md.h b/src/include/storage/md.h
index 9d7131eff43..f630b75446c 100644
--- a/src/include/storage/md.h
+++ b/src/include/storage/md.h
@@ -20,7 +20,7 @@
 #include "storage/smgr.h"
 #include "storage/sync.h"
 
-extern const PgAioHandleCallbacks aio_md_readv_cb;
+extern PGDLLIMPORT const PgAioHandleCallbacks aio_md_readv_cb;
 
 /* md storage manager functionality */
 extern void mdinit(void);
diff --git a/src/include/storage/smgr.h b/src/include/storage/smgr.h
index 856ebcda350..3964d9334b3 100644
--- a/src/include/storage/smgr.h
+++ b/src/include/storage/smgr.h
@@ -74,7 +74,7 @@ typedef SMgrRelationData *SMgrRelation;
 #define SmgrIsTemp(smgr) \
 	RelFileLocatorBackendIsTemp((smgr)->smgr_rlocator)
 
-extern const PgAioTargetInfo aio_smgr_target_info;
+extern PGDLLIMPORT const PgAioTargetInfo aio_smgr_target_info;
 
 extern void smgrinit(void);
 extern SMgrRelation smgropen(RelFileLocator rlocator, ProcNumber backend);