can't call foreign function: sched_setaffinity

[vlovich]

Running a basic test program against glommio:

$ MIRIFLAGS="-Zmiri-disable-isolation" cargo +nightly miri run --all-features --verbose
error: unsupported operation: can't call foreign function: sched_setaffinity
   --> /home/vlovich/.cargo/registry/src/github.com-1ecc6299db9ec823/nix-0.23.2/src/sched.rs:175:13
    |
175 | /             libc::sched_setaffinity(
176 | |                 pid.into(),
177 | |                 mem::size_of::<CpuSet>() as libc::size_t,
178 | |                 &cpuset.cpu_set,
179 | |             )
    | |_____________^ can't call foreign function: sched_setaffinity
    |
    = help: this is likely not a bug in the program; it indicates that the program performed an operation that the interpreter does not support
    = note: BACKTRACE:
    = note: inside `nix::sched::sched_linux_like::sched_setaffinity` at /home/vlovich/.cargo/registry/src/github.com-1ecc6299db9ec823/nix-0.23.2/src/sched.rs:175:13: 179:14
    = note: inside `glommio::executor::bind_to_cpu_set::<std::iter::Map<glommio::executor::placement::CpuIter, [closure@glommio::executor::placement::CpuIter::cpu_binding::{closure#0}]>>` at /home/vlovich/.cargo/registry/src/github.com-1ecc6299db9ec823/glommio-0.7.0/src/executor/mod.rs:220:5: 220:48

Not sure if it's expected to not work but figured I'd report it. I'm sure there may be others.

[RalfJung]

Yeah that function is not currently implemented by Miri. We could probably give a trivial implementation that does nothing, so this should be fairly easy to do.