Adding cython v0.20.2 in third-party.

third_party/cython/src/Cython/Plex/Actions.pxd

Index: third_party/cython/src/Cython/Plex/Actions.pxd
diff --git a/third_party/cython/src/Cython/Plex/Actions.pxd b/third_party/cython/src/Cython/Plex/Actions.pxd
new file mode 100644
index 0000000000000000000000000000000000000000..34660a2d9b18e92b5dd41ce7f24c9d549559a5d2
--- /dev/null
+++ b/third_party/cython/src/Cython/Plex/Actions.pxd
@@ -0,0 +1,25 @@
+
+cdef class Action:
+  cdef perform(self, token_stream, text)
+  cpdef same_as(self, other)
+
+cdef class Return(Action):
+  cdef object value
+  cdef perform(self, token_stream, text)
+  cpdef same_as(self, other)
+
+cdef class Call(Action):
+  cdef object function
+  cdef perform(self, token_stream, text)
+  cpdef same_as(self, other)
+
+cdef class Begin(Action):
+  cdef object state_name
+  cdef perform(self, token_stream, text)
+  cpdef same_as(self, other)
+
+cdef class Ignore(Action):
+  cdef perform(self, token_stream, text)
+
+cdef class Text(Action):
+  cdef perform(self, token_stream, text)