diff --git a/Makefile b/Makefile
index 44f8ee5af..ec293641b 100644
--- a/Makefile
+++ b/Makefile
@@ -22,6 +22,7 @@ endif
 
 .PHONY : all
 all :
+	@$(MAKE) -C src $(MAKE_FLAGS)
 	@$(MAKE) -C tools/mruby $(MAKE_FLAGS)
 
 # clean up