Support __version__ attribute in pure compiled mode.

Cython/Compiler/ParseTreeTransforms.py

@@ -2413,6 +2413,9 @@ class TransformBuiltinMethods(EnvTransform):
         if attribute:
             if attribute == u'compiled':
                 node = ExprNodes.BoolNode(node.pos, value=True)
+            if attribute == u'__version__':
+                import Cython
+                node = ExprNodes.StringNode(node.pos, value=EncodedString(Cython.__version__))
             elif attribute == u'NULL':
                 node = ExprNodes.NullNode(node.pos)
             elif attribute in (u'set', u'frozenset'):