Fix integer negation and absolute value to not rely
on undefined behaviour of the C compiler anymore.
Will backport to 2.5 and 2.4.
diff --git a/Misc/NEWS b/Misc/NEWS
index 0001f9f..2fb0793 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -12,6 +12,9 @@
 Core and builtins
 -----------------
 
+- Integer negation and absolute value were fixed to not rely
+  on undefined behaviour of the C compiler anymore.
+
 - Bug #1566800: make sure that EnvironmentError can be called with any
   number of arguments, as was the case in Python 2.4.