Cannot bind a non-const reference to a const lvalue; change this

function to return by value instead.


[SVN r61697]

libs/spirit

@@ -1 +1 @@
-Subproject commit 1f1bdb03c0251042f5638fbbca87f4f10d9cdefe
+Subproject commit 11da675df79cac4c236a6a2f1325c11559a5a87e