NOTE_FUNLOCK did not appear until macOS Sierra.
--- nqtail.c
+++ nqtail.c
@@ -184,9 +184,6 @@ main(int argc, char *argv[])
 #endif
 #ifdef USE_KEVENT
 		note = NOTE_WRITE;
-#ifdef __APPLE__
-		note |= NOTE_FUNLOCK;
-#endif
 #ifdef __FreeBSD__
 		note |= NOTE_CLOSE_WRITE;
 #endif
