* lisp/calendar/diary-icalendar.el (diary-icalendar--tz-is-utc-p): New
function.
(diary-icalendar-convert-time-via-strategy): Don't expect a VTIMEZONE
for UTC times.
(diary-icalendar-export-region): Don't generate a VTIMEZONE for 'local
export strategy in UTC.
* test/lisp/calendar/diary-icalendar-tests.el
(diary-icalendar-test-entry-parser): Don't generate a VTIMEZONE for
'local export strategy in UTC.
858cebd6c5