Make cStringIO.truncate raise IOError for negative
arguments (even for -1). Fixes the last bit of
#1359365.
diff --git a/Misc/NEWS b/Misc/NEWS
index 6fd73f6..9b2aeba 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -101,6 +101,9 @@
 Library
 -------
 
+- cStringIO.truncate(-1) now raises an IOError, like StringIO and
+  regular files.
+
 - Patch #1472877: Fix Tix subwidget name resolution.
 
 - Patch #1594554: Always close a tkSimpleDialog on ok(), even