fix 'cython.set' and 'cython.frozenset' when set/frozenset are declared names in the module

Cython/Compiler/ParseTreeTransforms.py

@@ -1262,7 +1262,8 @@ class TransformBuiltinMethods(EnvTransform):
             elif attribute == u'NULL':
                 node = NullNode(node.pos)
             elif attribute in (u'set', u'frozenset'):
-                node = NameNode(node.pos, name=EncodedString(attribute))
+                node = NameNode(node.pos, name=EncodedString(attribute),
+                                entry=self.current_env().builtin_scope().lookup_here(attribute))
             elif not PyrexTypes.parse_basic_type(attribute):
                 error(node.pos, u"'%s' not a valid cython attribute or is being used incorrectly" % attribute)
         return node

tests/run/set.pyx

@@ -12,6 +12,14 @@ def cython_set():
     assert set is cython.set
     return cython.set
 
+def cython_set_override():
+    """
+    >>> cython_set_override() is _set
+    True
+    """
+    set = 1
+    return cython.set
+
 def test_set_literal():
     """
     >>> type(test_set_literal()) is _set