Issue #6236, #6348: Fix various failures in the io module under AIX
and other platforms, when using a non-gcc compiler. Patch by egreen.

In addition, I made explicit the signedness of all bitfields in the
IO library.
diff --git a/Misc/NEWS b/Misc/NEWS
index 1cc8f74..89cbf3c 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -379,6 +379,9 @@
 Library
 -------
 
+- Issue #6236, #6348: Fix various failures in the `io` module under AIX
+  and other platforms, when using a non-gcc compiler. Patch by egreen.
+
 - Issue #6954: Fixed crash when using DISTUTILS_DEBUG flag in Distutils.
 
 - Issue #6851: Fix urllib.urlopen crash on secondairy threads on OSX 10.6