Tests Pass in GCC 4.4.7

Several tests either did not compile or failed upon running when using
GCC 4.4.7.

test/optional_test_ref_converting_ctor.cpp

@@ -93,7 +93,9 @@ template <typename T>
 void test_all_const_cases()
 {
   test_converting_ctor<T>();
+#ifndef BOOST_OPTIONAL_CONFIG_NO_PROPER_CONVERT_FROM_CONST_INT
   test_converting_ctor<const T>();
+#endif
   test_converting_ctor_for_noconst_const<T>();
 }