Workaround codegear ICE.

It seems that the problem is calling sizeof on a dependent type when the
containers have only been used by reference. So by putting in these
dummy structures with the containers as members, it helps the compiler
instantiate the class to the level where sizeof works. I hope.

[SVN r58130]

include/boost/unordered/detail/util.hpp

@@ -288,6 +288,9 @@ namespace boost { namespace unordered_detail {
     {
         if (node_) {
             if (value_constructed_) {
+#if BOOST_WORKAROUND(__CODEGEARC__, BOOST_TESTED_AT(0x0613))
+                struct dummy { hash_node<Alloc, Grouped> x; };
+#endif
                 boost::unordered_detail::destroy(&node_->value());
             }