bpo-36084: Add native thread ID to threading.Thread objects (GH-11993)

diff --git a/Lib/_dummy_thread.py b/Lib/_dummy_thread.py
index a2cae54..0a877e1 100644
--- a/Lib/_dummy_thread.py
+++ b/Lib/_dummy_thread.py
@@ -71,6 +71,10 @@
     """
     return 1
 
+def get_native_id():
+    """Dummy implementation of _thread.get_native_id()."""
+    return 0
+
 def allocate_lock():
     """Dummy implementation of _thread.allocate_lock()."""
     return LockType()