Issue #13411: memoryview objects are now hashable when the underlying object is hashable.
diff --git a/Include/object.h b/Include/object.h
index 648c9cb..b97f716 100644
--- a/Include/object.h
+++ b/Include/object.h
@@ -519,6 +519,7 @@
 #ifndef Py_LIMITED_API
 PyAPI_FUNC(Py_hash_t) _Py_HashDouble(double);
 PyAPI_FUNC(Py_hash_t) _Py_HashPointer(void*);
+PyAPI_FUNC(Py_hash_t) _Py_HashBytes(unsigned char*, Py_ssize_t);
 #endif
 
 /* Helper for passing objects to printf and the like */