Closes: https://github.com/emersion/xdg-desktop-portal-wlr/issues/60
Test basu unlike Alpine (elogind) and Arch (systemd).
Alpine uses musl, which may behave differently than glibc. Add Alpine to the CI to make sure we don't rely on glibc-specific behaviour. References: https://github.com/emersion/xdg-desktop-portal-wlr/issues/28