contrib/import-checker.py

--- a/contrib/import-checker.py	Tue Aug 22 14:12:21 2017 -0400
+++ b/contrib/import-checker.py	Tue Aug 22 14:12:37 2017 -0400
@@ -220,6 +220,7 @@
     # consider them stdlib.
     for m in ['msvcrt', '_winreg']:
         yield m
+    yield '__builtin__'
     yield 'builtins' # python3 only
     for m in 'fcntl', 'grp', 'pwd', 'termios':  # Unix only
         yield m