Drop support for EVENTVIEWS_NODECOS flag
No users known, so no need to complicate the code.
Seems this was once added in ancient times, cmp. history of build flag by commits unmaintained/kdepim@1c0dc477, unmaintained/kdepim@8b24c17e, unmaintained/kdepim@fecf24da
@winterz Would you have any further memories about it and its purpose, which might still be relevant today?