* lisp/mail/ietf-drums-date.el: parse-time-string replacement which is compatible but can be made stricter if desired. * test/lisp/mail/ietf-drums-date-tests.el (added): Add tests for ietf-drums-parse-date-string. * lisp/mail/ietf-drums.el (ietf-drums-parse-date): Use ietf-drums-parse-date-string.