+#endif // different hash_set/unordered_set possibilities
+
+#ifdef WX_HASH_SET_BASE_TEMPLATE
+
+// we need to define the class declared by _WX_DECLARE_HASH_SET as a class and
+// not a typedef to allow forward declaring it
+#define _WX_DECLARE_HASH_SET_IMPL( KEY_T, HASH_T, KEY_EQ_T, PTROP, CLASSNAME, CLASSEXP ) \
+CLASSEXP CLASSNAME \
+ : public WX_HASH_SET_BASE_TEMPLATE< KEY_T, HASH_T, KEY_EQ_T > \
+{ \
+public: \
+ explicit CLASSNAME(size_type n = 3, \
+ const hasher& h = hasher(), \
+ const key_equal& ke = key_equal(), \
+ const allocator_type& a = allocator_type()) \
+ : WX_HASH_SET_BASE_TEMPLATE< KEY_T, HASH_T, KEY_EQ_T >(n, h, ke, a) \
+ {} \
+ template <class InputIterator> \
+ CLASSNAME(InputIterator f, InputIterator l, \
+ const hasher& h = hasher(), \
+ const key_equal& ke = key_equal(), \
+ const allocator_type& a = allocator_type()) \
+ : WX_HASH_SET_BASE_TEMPLATE< KEY_T, HASH_T, KEY_EQ_T >(f, l, h, ke, a)\
+ {} \
+ CLASSNAME(const WX_HASH_SET_BASE_TEMPLATE< KEY_T, HASH_T, KEY_EQ_T >& s) \
+ : WX_HASH_SET_BASE_TEMPLATE< KEY_T, HASH_T, KEY_EQ_T >(s) \
+ {} \
+}
+
+// In some standard library implementations (in particular, the libstdc++ that
+// ships with g++ 4.7), std::unordered_set inherits privately from its hasher
+// and comparator template arguments for purposes of empty base optimization.
+// As a result, in the declaration of a class deriving from std::unordered_set
+// the names of the hasher and comparator classes are interpreted as naming
+// the base class which is inaccessible.
+// The workaround is to prefix the class names with 'struct'; however, don't
+// do this on MSVC because it causes a warning there if the class was
+// declared as a 'class' rather than a 'struct' (and MSVC's std::unordered_set
+// implementation does not suffer from the access problem).
+#ifdef _MSC_VER
+#define WX_MAYBE_PREFIX_WITH_STRUCT(STRUCTNAME) STRUCTNAME
+#else
+#define WX_MAYBE_PREFIX_WITH_STRUCT(STRUCTNAME) struct STRUCTNAME
+#endif
+
+#define _WX_DECLARE_HASH_SET( KEY_T, HASH_T, KEY_EQ_T, PTROP, CLASSNAME, CLASSEXP ) \
+ _WX_DECLARE_HASH_SET_IMPL( \
+ KEY_T, \
+ WX_MAYBE_PREFIX_WITH_STRUCT(HASH_T), \
+ WX_MAYBE_PREFIX_WITH_STRUCT(KEY_EQ_T), \
+ PTROP, \
+ CLASSNAME, \
+ CLASSEXP)
+
+#else // no appropriate STL class, use our own implementation