+JH/30 Fix a logging bug on aarch64: an unsafe routine was previously used for
+ a possibly-overlapping copy. The symptom was that "Remote host closed
+ connection in response to HELO" was logged instead of the actual 4xx
+ error for the HELO.
+
+JH/31 Fix CHUNKING code to properly flush the unwanted chunk after an error.
+ Previously only that bufferd was discarded, resulting in SYMTP command
+ desynchronisation.
+