Adding cython v0.20.2 in third-party.

third_party/cython/src/Cython/Includes/libcpp/list.pxd

Index: third_party/cython/src/Cython/Includes/libcpp/list.pxd
diff --git a/third_party/cython/src/Cython/Includes/libcpp/list.pxd b/third_party/cython/src/Cython/Includes/libcpp/list.pxd
new file mode 100644
index 0000000000000000000000000000000000000000..ad8eb08cb64db46d524d386139464acd090f3173
--- /dev/null
+++ b/third_party/cython/src/Cython/Includes/libcpp/list.pxd
@@ -0,0 +1,69 @@
+cdef extern from "<list>" namespace "std":
+    cdef cppclass list[T]:
+        cppclass iterator:
+            iterator()
+            iterator(iterator &)
+            T& operator*() nogil
+            iterator operator++() nogil
+            iterator operator--() nogil
+            bint operator==(iterator) nogil
+            bint operator!=(iterator) nogil
+        cppclass reverse_iterator:
+            reverse_iterator()
+            reverse_iterator(iterator &)
+            T& operator*() nogil
+            reverse_iterator operator++() nogil
+            reverse_iterator operator--() nogil
+            bint operator==(reverse_iterator) nogil
+            bint operator!=(reverse_iterator) nogil
+        #cppclass const_iterator(iterator):
+        #    pass
+        #cppclass const_reverse_iterator(reverse_iterator):
+        #    pass
+        list() nogil except +
+        list(list&) nogil except +
+        list(size_t, T&) nogil except +
+        #list operator=(list&)
+        bint operator==(list&, list&) nogil
+        bint operator!=(list&, list&) nogil
+        bint operator<(list&, list&) nogil
+        bint operator>(list&, list&) nogil
+        bint operator<=(list&, list&) nogil
+        bint operator>=(list&, list&) nogil
+        void assign(size_t, T&) nogil
+        T& back() nogil
+        iterator begin() nogil
+        #const_iterator begin()
+        void clear() nogil
+        bint empty() nogil
+        iterator end() nogil
+        #const_iterator end()
+        iterator erase(iterator) nogil
+        iterator erase(iterator, iterator) nogil
+        T& front() nogil
+        iterator insert(iterator, T&) nogil
+        void insert(iterator, size_t, T&) nogil
+        size_t max_size() nogil
+        void merge(list&) nogil
+        #void merge(list&, BinPred)
+        void pop_back() nogil
+        void pop_front() nogil
+        void push_back(T&) nogil
+        void push_front(T&) nogil
+        reverse_iterator rbegin() nogil
+        #const_reverse_iterator rbegin()
+        void remove(T&) nogil
+        #void remove_if(UnPred)
+        reverse_iterator rend() nogil
+        #const_reverse_iterator rend()
+        void resize(size_t, T&) nogil
+        void reverse() nogil
+        size_t size() nogil
+        void sort() nogil
+        #void sort(BinPred)
+        void splice(iterator, list&) nogil
+        void splice(iterator, list&, iterator) nogil
+        void splice(iterator, list&, iterator, iterator) nogil
+        void swap(list&) nogil
+        void unique() nogil
+        #void unique(BinPred)