[iter] Fix hb_sink() to accept rvalue
diff --git a/src/hb-iter.hh b/src/hb-iter.hh
index aa5eb9c..a339013 100644
--- a/src/hb-iter.hh
+++ b/src/hb-iter.hh
@@ -569,7 +569,7 @@
 template <typename Sink>
 struct hb_sink_t
 {
-  hb_sink_t (Sink&& s) : s (s) {}
+  hb_sink_t (Sink s) : s (s) {}
 
   template <typename Iter,
 	    hb_requires (hb_is_iterator (Iter))>