diff --git a/src/include/postmaster/bgworker.h b/src/include/postmaster/bgworker.h
index e0f468fab9e..57e95fe3186 100644
--- a/src/include/postmaster/bgworker.h
+++ b/src/include/postmaster/bgworker.h
@@ -82,7 +82,7 @@ typedef struct BackgroundWorker
 extern void RegisterBackgroundWorker(BackgroundWorker *worker);
 
 /* This is valid in a running worker */
-extern BackgroundWorker *MyBgworkerEntry;
+extern PGDLLIMPORT BackgroundWorker *MyBgworkerEntry;
 
 /*
  * Connect to the specified database, as the specified user.  Only a worker