diff --git a/include/os.h b/include/os.h
index 2d164563a..84d4f7b58 100644
--- a/include/os.h
+++ b/include/os.h
@@ -86,8 +86,6 @@ typedef struct _NewClientRec *NewClientPtr;
 
 extern _X_EXPORT int ReadFdFromClient(ClientPtr client);
 
-extern _X_EXPORT void FlushIfCriticalOutputPending(void);
-
 extern _X_EXPORT void SetCriticalOutputPending(void);
 
 extern _X_EXPORT int WriteToClient(ClientPtr /*who */ , int /*count */ ,
diff --git a/os/client_priv.h b/os/client_priv.h
index 04649c8d4..0a9ea08bb 100644
--- a/os/client_priv.h
+++ b/os/client_priv.h
@@ -47,6 +47,7 @@ int ReadRequestFromClient(struct _Client *client);
 int WriteFdToClient(struct _Client *client, int fd, Bool do_close);
 Bool InsertFakeRequest(struct _Client *client, char *data, int count);
 void FlushAllOutput(void);
+void FlushIfCriticalOutputPending(void);
 
 /* exported only for DRI module, but should not be used by external drivers */
 _X_EXPORT void ResetCurrentRequest(struct _Client *client);