[layout] Use setter method to set c->lookup_props
diff --git a/src/hb-ot-layout-gsub-table.hh b/src/hb-ot-layout-gsub-table.hh
index aaf3b51..6495335 100644
--- a/src/hb-ot-layout-gsub-table.hh
+++ b/src/hb-ot-layout-gsub-table.hh
@@ -1382,7 +1382,7 @@
   unsigned int saved_lookup_props = c->lookup_props;
   c->set_lookup (l);
   bool ret = l.apply_once (c);
-  c->lookup_props = saved_lookup_props;
+  c->set_lookup_props (saved_lookup_props);
   return ret;
 }