Build failure on OpenBSD with Rust nightly.

[vext01]

During cargo install mdbook:

   Compiling ansi_term v0.9.0
error[E0425]: cannot find value `EV_RECEIPT` in module `libc`
  --> .cargo/registry/src/github.com-1ecc6299db9ec823/mio-0.6.5/src/sys/unix/kqueue.rs:84:27
   |
84 |                     libc::EV_RECEIPT;
   |                           ^^^^^^^^^^ not found in `libc`

error[E0425]: cannot find value `EV_RECEIPT` in module `libc`
   --> .cargo/registry/src/github.com-1ecc6299db9ec823/mio-0.6.5/src/sys/unix/kqueue.rs:120:50
    |
120 |             let filter = libc::EV_DELETE | libc::EV_RECEIPT;
    |                                                  ^^^^^^^^^^ not found in `libc`

Nightly from yesterday on amd64/openbsd.

Thanks

[kpcyrd]

I'm not sure this is related to rust-ansi-term, since it doesn't have a dependency to mio which is failing to build. Cargo runs builds for depencies concurrently if I'm not mistaken.

Some of the other depencies of mdbook have a depency to mio, which doesn't build on openbsd yet. This has been reported as tokio-rs/mio#593