[array] Add constructor from hb_array_t<const Type>
diff --git a/src/hb-array.hh b/src/hb-array.hh
index 83211aa..61037e2 100644
--- a/src/hb-array.hh
+++ b/src/hb-array.hh
@@ -41,6 +41,7 @@
 
   hb_array_t (void) : arrayZ (nullptr), len (0) {}
   hb_array_t (const hb_array_t &o) : arrayZ (o.arrayZ), len (o.len) {}
+  hb_array_t (hb_array_t<const Type> o) : arrayZ (o.arrayZ), len (o.len) {}
   hb_array_t (Type *array_, unsigned int len_) : arrayZ (array_), len (len_) {}
 
   Type& operator [] (int i_) const