A looooong time ago, we had to manually hijack stdio for FreeBSD to suppress a bogus stderr warning (see
#798). I filed an upstream report at GuillaumeGomez/sysinfo#875, but the real issue was actually with FreeBSD itself. From the upstream upstream bug report at https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=228432, it looks like this has been fixed since 2022 for FreeBSD 13, so I think it's safe to remove this hack at this point on our end, especially given that I don't build binaries for older than FreeBSD 13 anymore (oldest is 15 now).
This PR allows us to entirely remove the filedescriptor crate for FreeBSD since we no longer use it entirely.
This change should fix the issue around `cargo install` being confused by the schema generation binary by just moving it entirely into a separate tool "crate".
Clement Tsang