diff --git a/configure.ac b/configure.ac
index 02eb5fa..8c81f9a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -59,7 +59,9 @@ if [[ -n "$ksourcedir" ]]; then
 	kinclude_CFLAGS="$kinclude_CFLAGS -I $ksourcedir/include";
 fi;
 
-AC_SUBST([regular_CFLAGS xtables_CFLAGS kinclude_CFLAGS])
+AC_SUBST([regular_CFLAGS])
+AC_SUBST([xtables_CFLAGS])
+AC_SUBST([kinclude_CFLAGS])
 AC_SUBST([kbuilddir])
 AC_SUBST([ksourcedir])
 AC_SUBST([xtlibdir])