NEWS: Highlight libopenvswitch API change caused by UB fixes.

Acked-by: Dumitru Ceara <[email protected]>
Signed-off-by: Ilya Maximets <[email protected]>

NEWS

@@ -1,5 +1,16 @@
 Post-v2.17.0
 ---------------------
+   - libopenvswitch API change:
+     * To fix the Undefined Behavior issue causing the compiler to incorrectly
+       optimize important parts of code, container iteration macros (e.g.,
+       LIST_FOR_EACH) have been re-implemented in a UB-safe way.
+     * Backwards compatibility has mostly been preserved, however the
+       user-provided pointer is now set to NULL after the loop (unless it
+       exited via "break;")
+     * Users of libopenvswitch will need to double-check the use of such loop
+       macros before compiling with a new version.
+     * Since the change is limited to the definitions within the headers, the
+       ABI is not affected.
    - OVSDB:
      * 'relay' service model now supports transaction history, i.e. honors the
        'last-txn-id' field in 'monitor_cond_since' requests from clients.