swaits
a92eda210e
The update module is `#[cfg(unix)]` (self-update replaces the running
program's file, which Windows forbids), but three commands in
`ledger-host` used `crate::update` unconditionally, so the server-only
Windows build could not resolve the module. GitHub's portable-windows
job failed on main 3aa1206a with nine E0433 errors in `ledger-host`.
Gate `update_waiting`, `check_for_updates` and `apply_update` with
`#[cfg(unix)]`, leaving their Unix bodies unchanged, and give non-unix
builds a stub of each: nothing is waiting, and checking for or accepting
an update is refused with "self-update isn't available on this platform"
(the same `Err` path a refused update takes). `UPDATE_WAIT` is gated with
the Unix `apply_update` it serves.