diff --git a/mk/util.mk b/mk/util.mk
index e761aeb21..2ce48583f 100644
--- a/mk/util.mk
+++ b/mk/util.mk
@@ -30,8 +30,7 @@ SUPPORTED_PLATFORMS += openbsd-amd64
 SUPPORTED_PLATFORMS += netbsd-386
 SUPPORTED_PLATFORMS += netbsd-amd64
 
-space:=
-space+=
+space:=$() $()
 comma:=,
 join-with=$(subst $(space),$1,$(strip $2))