diff --git a/src/include/storage/procsignal.h b/src/include/storage/procsignal.h
index d571958bda5..c6255620f3d 100644
--- a/src/include/storage/procsignal.h
+++ b/src/include/storage/procsignal.h
@@ -54,6 +54,6 @@ extern int SendProcSignal(pid_t pid, ProcSignalReason reason,
 			   BackendId backendId);
 
 extern void procsignal_sigusr1_handler(SIGNAL_ARGS);
-extern bool set_latch_on_sigusr1;
+extern PGDLLIMPORT bool set_latch_on_sigusr1;
 
 #endif   /* PROCSIGNAL_H */