Adding cython v0.20.2 in third-party.

third_party/cython/src/Cython/Includes/cpython/bool.pxd

Index: third_party/cython/src/Cython/Includes/cpython/bool.pxd
diff --git a/third_party/cython/src/Cython/Includes/cpython/bool.pxd b/third_party/cython/src/Cython/Includes/cpython/bool.pxd
new file mode 100644
index 0000000000000000000000000000000000000000..c775088ce645244ec7be27faeba194a37cb626bd
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+++ b/third_party/cython/src/Cython/Includes/cpython/bool.pxd
@@ -0,0 +1,38 @@
+
+cdef extern from "Python.h":
+
+    ############################################################################
+    # 7.2.2 Boolean Objects
+    ############################################################################
+
+    ctypedef class __builtin__.bool [object PyBoolObject]:
+        pass
+
+    # Booleans in Python are implemented as a subclass of
+    # integers. There are only two booleans, Py_False and Py_True. As
+    # such, the normal creation and deletion functions don't apply to
+    # booleans. The following macros are available, however.
+
+    bint PyBool_Check(object o)
+    # Return true if o is of type PyBool_Type.
+
+    #PyObject* Py_False
+    # The Python False object. This object has no methods. It needs to
+    # be treated just like any other object with respect to reference
+    # counts.
+
+    #PyObject* Py_True
+    # The Python True object. This object has no methods. It needs to
+    # be treated just like any other object with respect to reference
+    # counts.
+
+    # Py_RETURN_FALSE
+    # Return Py_False from a function, properly incrementing its reference count.
+
+    # Py_RETURN_TRUE
+    # Return Py_True from a function, properly incrementing its reference count.
+
+    object PyBool_FromLong(long v)
+    # Return value: New reference.
+    # Return a new reference to Py_True or Py_False depending on the truth value of v.
+