[meta] Fix addressof()
diff --git a/src/hb-meta.hh b/src/hb-meta.hh
index 132e644..6eb1315 100644
--- a/src/hb-meta.hh
+++ b/src/hb-meta.hh
@@ -71,7 +71,7 @@
 struct
 {
   template <typename T>
-  T* operator () (const T& arg) const
+  T* operator () (T& arg) const
   {
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wcast-align"