diff --git a/Makefile b/Makefile
index 9bf8426..30211c0 100644
--- a/Makefile
+++ b/Makefile
@@ -7,4 +7,4 @@ apidoc:
 	smldoc --windowtitle="SU4SML API Documentation" --hidebysig --directory=doc/api --linksource --showsummary --overview=doc/overview.html src/su4sml.cm
 
 su4sml:
-	cd src && echo "val _ = use \"ROOT.ML\"" | sml	
+	(cd src && echo "val _ = use \"ROOT.ML\"" | sml )