Adding cython v0.20.2 in third-party.

third_party/cython/src/Cython/Compiler/ParseTreeTransforms.pxd

Index: third_party/cython/src/Cython/Compiler/ParseTreeTransforms.pxd
diff --git a/third_party/cython/src/Cython/Compiler/ParseTreeTransforms.pxd b/third_party/cython/src/Cython/Compiler/ParseTreeTransforms.pxd
new file mode 100644
index 0000000000000000000000000000000000000000..58d4795ae0fba7a1f0af6b61ab3ec595971c60a4
--- /dev/null
+++ b/third_party/cython/src/Cython/Compiler/ParseTreeTransforms.pxd
@@ -0,0 +1,69 @@
+
+cimport cython
+
+from Cython.Compiler.Visitor cimport (
+    CythonTransform, VisitorTransform, TreeVisitor,
+    ScopeTrackingTransform, EnvTransform)
+
+cdef class NameNodeCollector(TreeVisitor):
+    cdef list name_nodes
+
+cdef class SkipDeclarations: # (object):
+    pass
+
+cdef class NormalizeTree(CythonTransform):
+    cdef bint is_in_statlist
+    cdef bint is_in_expr
+    cpdef visit_StatNode(self, node, is_listcontainer=*)
+
+cdef class PostParse(ScopeTrackingTransform):
+    cdef dict specialattribute_handlers
+    cdef size_t lambda_counter
+    cdef size_t genexpr_counter
+    cdef _visit_assignment_node(self, node, list expr_list)
+
+
+#def eliminate_rhs_duplicates(list expr_list_list, list ref_node_sequence)
+#def sort_common_subsequences(list items)
+@cython.locals(starred_targets=Py_ssize_t, lhs_size=Py_ssize_t, rhs_size=Py_ssize_t)
+cdef flatten_parallel_assignments(list input, list output)
+cdef map_starred_assignment(list lhs_targets, list starred_assignments, list lhs_args, list rhs_args)
+
+#class PxdPostParse(CythonTransform, SkipDeclarations):
+#class InterpretCompilerDirectives(CythonTransform, SkipDeclarations):
+#class WithTransform(CythonTransform, SkipDeclarations):
+#class DecoratorTransform(CythonTransform, SkipDeclarations):
+
+#class AnalyseDeclarationsTransform(EnvTransform):
+
+cdef class AnalyseExpressionsTransform(CythonTransform):
+    pass
+
+cdef class ExpandInplaceOperators(EnvTransform):
+    pass
+
+cdef class AlignFunctionDefinitions(CythonTransform):
+    cdef dict directives
+    cdef scope
+
+cdef class YieldNodeCollector(TreeVisitor):
+    cdef public list yields
+    cdef public list returns
+    cdef public bint has_return_value
+
+cdef class MarkClosureVisitor(CythonTransform):
+    cdef bint needs_closure
+
+cdef class CreateClosureClasses(CythonTransform):
+    cdef list path
+    cdef bint in_lambda
+    cdef module_scope
+    cdef generator_class
+
+cdef class GilCheck(VisitorTransform):
+    cdef list env_stack
+    cdef bint nogil
+    cdef bint nogil_declarator_only
+
+cdef class TransformBuiltinMethods(EnvTransform):
+    cdef visit_cython_attribute(self, node)