mio: Mio build broken on Haiku, no kpoll/kqueue

   Compiling parking_lot v0.9.0
   Compiling hyper v0.12.35
   Compiling aho-corasick v0.7.15
   Compiling addr2line v0.14.0
   Compiling idna v0.1.5
   Compiling idna v0.2.0
   Compiling mime_guess v2.0.3
   Compiling futures-cpupool v0.1.8
   Compiling bytes v0.4.12
   Compiling mio v0.6.23
error[E0432]: unresolved imports `self::unix::Events`, `self::unix::Selector`
 --> /boot/home/.cargo/registry/src/github.com-1ecc6299db9ec823/mio-0.6.23/src/sys/mod.rs:5:5
  |
5 |     Events,
  |     ^^^^^^ no `Events` in `sys::unix`
6 |     Io,
7 |     Selector,
  |     ^^^^^^^^ no `Selector` in `sys::unix`

error: aborting due to previous error

For more information about this error, try `rustc --explain E0432`.
error: could not compile `mio`