diff --git a/microscript/ILibDuktape_fs.c b/microscript/ILibDuktape_fs.c
index 8a754e0..cf1c59a 100644
--- a/microscript/ILibDuktape_fs.c
+++ b/microscript/ILibDuktape_fs.c
@@ -108,6 +108,7 @@ typedef struct ILibDuktape_fs_appleWatcher
 	void *chain;
 	void *kthread;									// Worker thread running kevent()
 	int kq;											// kqueue() object
+	sem_t exitWaiter;
 	sem_t inputWaiter;								// Semaphore used to dispatch between Microstack Event Loop and kevent loop.
 	int unblocker[2];								// pipe used to unblock thread
 	ILibDuktape_fs_descriptorInfo **descriptors;