Currently if I build tiny without --features desktop-notifications or get one of the pre-built binaries without this feature I can still use the /notify command, but notifications just don't work. This is confusing as very recently two users (1, 2) got confused by it.

Instead /notify should print a warning like

Desktop notifications are not enabled in this build. Please see README for
building with desktop notifications, or get a pre-built binary with libdbus in
releases page.