Allows
* projects linking to KIO 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
* -DKIOFILEWIDGETS_DISABLE_DEPRECATED_BEFORE_AND_AT
* -DKIOFILEWIDGETS_NO_DEPRECATED
* -DKIOFILEWIDGETS_DEPRECATED_WARNINGS_SINCE
* -DKIOFILEWIDGETS_NO_DEPRECATED_WARNINGS
* -DKIOWIDGETS_DISABLE_DEPRECATED_BEFORE_AND_AT
* -DKIOWIDGETS_NO_DEPRECATED
* -DKIOWIDGETS_DEPRECATED_WARNINGS_SINCE
* -DKIOWIDGETS_NO_DEPRECATED_WARNINGS
or (once enabled when all KF modules are done)
* -DKF_DISABLE_DEPRECATED_BEFORE_AND_AT
* -DKF_NO_DEPRECATED
* -DKF_DEPRECATED_WARNINGS_SINCE
* -DKF_NO_DEPRECATED_WARNINGS
No support for "EXCLUDE_DEPRECATED_BEFORE_AND_AT" yet, some
undeprecated API is implemented by deprecated API still, at least for
some deprecation versions. This needs separate work.