diff --git a/tests/examples/gl/Makefile.am b/tests/examples/gl/Makefile.am
index 3acca8fdcd..d43431e476 100644
--- a/tests/examples/gl/Makefile.am
+++ b/tests/examples/gl/Makefile.am
@@ -26,3 +26,5 @@ endif
 endif
 
 DIST_SUBDIRS=cocoa generic qt clutter sdl gtk
+
+include $(top_srcdir)/common/parallel-subdirs.mak