The test cover:
- All possible priorities and facilities through TCP and UDP.
- Same syslog tests for vsyslog.
- Some openlog/syslog/close combinations.
- openlog with LOG_CONS, LOG_PERROR, and LOG_PID.
Internally is done with a test-container where the main process mimics
the syslog server interface.
The test does not cover multithread and async-signal usage.
Checked on x86_64-linux-gnu.
