Add -3 warnings that set.copy(), dict.copy(), and defaultdict.copy() will go away in Py3.x
diff --git a/Objects/setobject.c b/Objects/setobject.c
index cc2c2ee..3869b3b 100644
--- a/Objects/setobject.c
+++ b/Objects/setobject.c
@@ -1131,8 +1131,22 @@
 }
 
 static PyObject *
+set_copy_method(PySetObject *so)
+{
+	if (Py_Py3kWarningFlag &&
+	    PyErr_Warn(PyExc_DeprecationWarning, 
+		       "set.copy() not supported in 3.x") < 0)
+		return NULL;
+	return make_new_set(Py_TYPE(so), (PyObject *)so);
+}
+
+static PyObject *
 frozenset_copy(PySetObject *so)
 {
+	if (Py_Py3kWarningFlag &&
+	    PyErr_Warn(PyExc_DeprecationWarning, 
+		       "frozenset.copy() not supported in 3.x") < 0)
+		return NULL;
 	if (PyFrozenSet_CheckExact(so)) {
 		Py_INCREF(so);
 		return (PyObject *)so;
@@ -1911,7 +1925,7 @@
 	 clear_doc},
 	{"__contains__",(PyCFunction)set_direct_contains,	METH_O | METH_COEXIST,
 	 contains_doc},
-	{"copy",	(PyCFunction)set_copy,		METH_NOARGS,
+	{"copy",	(PyCFunction)set_copy_method,	METH_NOARGS,
 	 copy_doc},
 	{"discard",	(PyCFunction)set_discard,	METH_O,
 	 discard_doc},