diff --git a/vars/libxslt.vars b/vars/libxslt.vars
index d02e695..853f22d 100644
--- a/vars/libxslt.vars
+++ b/vars/libxslt.vars
@@ -2,6 +2,10 @@
 # set +o errexit -o noglob -o nounset is assumed.
 #
 
+: ${PKG_LIBXSLT_CONFIG_CACHE_EXTRA:="
+ac_cv_path_ac_pt_XML_CONFIG=no
+ac_cv_path_XML_CONFIG=no"};
+
 pkg_libxslt_install_make_post() {
 	if ! rtl_fileop mkdir "${PKG_DESTDIR_HOST}/bin"; then
 		return 1;