diff --git a/simgear/Makefile.am b/simgear/Makefile.am
index 855b42dc..106162cd 100644
--- a/simgear/Makefile.am
+++ b/simgear/Makefile.am
@@ -44,7 +44,7 @@ SUBDIRS = \
 	screen \
 	$(SERIAL_DIRS) \
 	sky \
-	$(SGTHREAD_DIR)
+	$(SGTHREAD_DIR) \
 	timing \
 	xgl \
 	$(ZLIB_DIRS)