Fixed signal handling on BSD, I/O h. interrupts, bugfixes.

src/common/evqueue.c

src/knot/main.c

src/knot/other/log.c

src/knot/server/dthreads.c

src/knot/server/server.c

src/knot/server/server.h

src/knot/server/tcp-handler.c

src/tests/unittests_main.c

src/zcompile/zcompile.c