`#[derive(PartialEq, Eq)]` for `nix::Errno`?

[dpc]

match nix::unistd::read(*self.stdio.stdin.get_ref().0, self.buf) {
    Err(nix::Error::Sys(nix::errno::EWOULDBLOCK)) => {
    ...
    },
    ...
}

produces:

src/lib.rs|84 col 37 warning| to use a constant of type `nix::Errno` in a pattern, `nix::Errno` must be annotated with `#[derive(PartialEq, Eq)]`, #[warn(illegal_struct_or_e
num_constant_pattern)] on by default                                                                                                                                         
|| this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!                                                    
|| for more information, see RFC 1445 <https://github.com/rust-lang/rfcs/pull/1445>  

I'm not exactly sure if I do the matching the best way.

[Susurrus]

Errno already implemented PartialEq, but Eq will be added by #807. Until that's merged, though, we'll leave this issue open.