How to reproduce:
1. Start himitsud.
2. Trigger launch of grant prompter (e.g. with `hiq -d`).
3. Kill the propmter.
himitsud aborts after killing the prompter with following error:
Abort: .../himitsu/cmd/himitsud/cmd.ha:20:1: execution reached unreachable code (compiler bug)
That line is the match expression of himitsud::cmd::strerror(). The
code looks correct, the match expression is exhaustive. There is a
chance this is a Hare bug, probably a variant of