Add missing import of errno.
diff --git a/Lib/test/test_posix.py b/Lib/test/test_posix.py
index ac3dbb8..a2eba89 100644
--- a/Lib/test/test_posix.py
+++ b/Lib/test/test_posix.py
@@ -7,6 +7,7 @@
 except ImportError:
     raise test_support.TestSkipped, "posix is not available"
 
+import errno
 import time
 import os
 import pwd