Cleanly integrate tansiv-client logs with client app (Qemu) logs
Logs in tansiv-client are currently managed internally in the library and thus may not be output in the same stream as the client app logs (Qemu logs, or app-specific logs with tanproc). For a better integration the library logs should at least go to a file descriptor provided by the client app.
A few concerns to think about:
- Format of the logs: should the library use a client-provided function to format the logs? (library formatting encapsulated in client app formatting)
- Keep this compatible with internal non reg tests.
- How to deal with logs output by the deadline handler, especially in tanproc?
- Keep the library logs configurable.