VS2013 doesn't allow move ops to be =default
diff --git a/include/json/value.h b/include/json/value.h
index 9a2d10d..a62f482 100644
--- a/include/json/value.h
+++ b/include/json/value.h
@@ -659,9 +659,9 @@
   public:
     Comments() = default;
     Comments(const Comments& that);
-    Comments(Comments&&) = default;
+    Comments(Comments&& that);
     Comments& operator=(const Comments& that);
-    Comments& operator=(Comments&&) = default;
+    Comments& operator=(Comments&& that);
     bool has(CommentPlacement slot) const;
     String get(CommentPlacement slot) const;
     void set(CommentPlacement slot, String s);