diff --git a/examples/custom-utop/Makefile b/examples/custom-utop/Makefile
index c55811a..296aad4 100644
--- a/examples/custom-utop/Makefile
+++ b/examples/custom-utop/Makefile
@@ -1,7 +1,7 @@
 OC := ocamlbuild -classic-display -no-links -use-ocamlfind
 
 build:
-	$(OC) -pkg threads,utop myutop.top
+	$(OC) -tag thread -pkg threads,utop myutop.top
 
 clean:
 	$(OC) -clean