Previously the destructors of classes derived from Source were not
called when destructing a Source because Source missed the declaration
of a virtual destructor. This caused at least problems when
reconstructing a Chargen_source with its Chargen_repeater that includes
a One_shot_timeout. In this case, the members of the Alarm behind the
timeout were not reset and the next time beeing used the Alarm appeared
to be still active which wasn't true.
Fixes#2570
The input_filter is the successor of the input_merger. In addition to
merging input streams, the component applies several forms of input
transformations such as the application of keyboard layouts.
Issue #2264
Martin Stein
Norman Feske