Add a format specifier %R to PyUnicode_FromFormat(), which embeds
the result of a call to PyObject_Repr() into the string. This makes
it possible to simplify many repr implementations.

PyUnicode_FromFormat() uses two steps to create the final string: A first
pass through the format string determines the size of the final string and
a second pass creates the string. To avoid calling PyObject_Repr() twice
for each %R specifier, PyObject_Repr() is called during the size
calculation step and the results are stored in an array (whose size is
determined at the start by counting %R specifiers).
diff --git a/Objects/classobject.c b/Objects/classobject.c
index e4687a3..b7711d5 100644
--- a/Objects/classobject.c
+++ b/Objects/classobject.c
@@ -261,11 +261,9 @@
 		result = PyUnicode_FromFormat("<unbound method %s.%s>",
 					     sklassname, sfuncname);
 	else {
-		result = PyUnicode_FromFormat("<bound method %s.%s of ",
-		                              sklassname, sfuncname);
-		/* XXX Shouldn't use repr() here! */
-		PyUnicode_AppendAndDel(&result, PyObject_Repr(self));
-		PyUnicode_AppendAndDel(&result, PyUnicode_FromString(">"));
+		/* XXX Shouldn't use repr()/%R here! */
+		result = PyUnicode_FromFormat("<bound method %s.%s of %R>",
+		                              sklassname, sfuncname, self);
 	}
 	Py_XDECREF(funcname);
 	Py_XDECREF(klassname);