The previous fire-and-forget fix passed hwd's own INIT_NOTIFY fd to pcid,
but that fd had CLOEXEC set (by daemon::Daemon::new), so pcid inherited
a closed fd and panicked in PipeWriter::from_raw_fd.
Fix: create a new pipe in hwd before spawning pcid. Pass the write end
as INIT_NOTIFY with CLOEXEC cleared (via pre_exec). Drop the read end
immediately — pcid's daemon.ready() will get EPIPE, which is silently
ignored by the daemon library. This gives pcid a valid fd while still
being fully non-blocking from hwd's perspective.
vasilito
183354fcb1