Issue #9260: A finer-grained import lock.

Most of the import sequence now uses per-module locks rather than the
global import lock, eliminating well-known issues with threads and imports.
diff --git a/Lib/token.py b/Lib/token.py
index 6b5320d..31fae0a 100755
--- a/Lib/token.py
+++ b/Lib/token.py
@@ -70,7 +70,7 @@
 
 tok_name = {value: name
             for name, value in globals().items()
-            if isinstance(value, int)}
+            if isinstance(value, int) and not name.startswith('_')}
 __all__.extend(tok_name.values())
 
 def ISTERMINAL(x):