Tighten parsing of DKIM header records. Previously, all but lowercase
alpha chars would be ignored in potential tag names.
+JH/09 Bug 3057: Add heuristic for spotting mistyped IPv6 addresses in lists
+ being searched. Previously we only had one for IPv4 addresses. Per the
+ documentation, the error results by default in a no-match result for the
+ list. It is logged if the unknown_in_list log_selector is used.
+
Exim version 4.97