diff --git a/Makefile.am b/Makefile.am
index 985e8eff4..b15b9f54c 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -82,7 +82,7 @@ rootprefix=@rootprefix@
 rootbindir=$(rootprefix)/bin
 rootlibexecdir=$(rootprefix)/lib/systemd
 
-CLEANFILES = BUILT_SOURCES
+CLEANFILES = $(BUILT_SOURCES)
 EXTRA_DIST =
 BUILT_SOURCES =
 INSTALL_EXEC_HOOKS =