Allows
* projects linking to KCalendarCore to hide deprecated API up to a
given version or silence deprecation warnings after a given version,
using
* -DKIOCORE_DISABLE_DEPRECATED_BEFORE_AND_AT
* -DKIOCORE_NO_DEPRECATED
* -DKIOCORE_DEPRECATED_WARNINGS_SINCE
* -DKIOCORE_NO_DEPRECATED_WARNINGS
* -DKIOKIOFILEWIDGETS_DISABLE_DEPRECATED_BEFORE_AND_AT
* -DKIOKIOFILEWIDGETS_NO_DEPRECATED
* -DKIOKIOFILEWIDGETS_DEPRECATED_WARNINGS_SINCE
* -DKIOKIOFILEWIDGETS_NO_DEPRECATED_WARNINGS
* -DKIOWIDGETS_DISABLE_DEPRECATED_BEFORE_AND_AT
* -DKIOWIDGETS_NO_DEPRECATED
* -DKIOWIDGETS_DEPRECATED_WARNINGS_SINCE
* -DKIOWIDGETS_NO_DEPRECATED_WARNINGS
or
* -DKF_DISABLE_DEPRECATED_BEFORE_AND_AT
* -DKF_NO_DEPRECATED
* -DKF_DEPRECATED_WARNINGS_SINCE
* -DKF_NO_DEPRECATED_WARNINGS