POSIX mqueue bindings for the BSDs

Note that OpenBSD and OSX do not support POSIX message queues.

Note that OpenBSD and OSX do not support POSIX message queues.

Add `net/if_utun.h` and `linux/if_tun.h` constants for macos and linux platform

Add `net/if_utun.h` constants for macos platform.

Add `linux/if_tun.h` constants for linux platform.

Openbsd aarch64

it adds aarch64-unknown-openbsd definition (and push `c_char` deeper, so the amount of changes).

I also updated errno definitions for openbsd

move c_char definition more deeper to make it 'u8' on
aarch64-unknown-openbsd.

Add struct `sockaddr_dl` for bsdlike platforms

Freebsd: https://github.com/freebsd/freebsd/blob/master/sys/net/if_dl.h#L59
Macos: https://github.com/apple/darwin-xnu/blob/master/bsd/net/if_dl.h#L95

Add missing EAI_* flags for multiple platforms

Add missing EAI_* flags for multiple platforms.

Ucreds

I'm not positive on the `SOCKCREDSIZE()` implementation, but we'll see what CI says I guess.

Removes a compilation warning

Minor fixes for mips-unknown-linux-uclibc

Just adding a few definitions so the toolchain compiles

Add more FreeBSD errnos

Add additional errno constants for NetBSD

Bump to 0.2.34

Use IFF_OACTIVE and IFF_RUNNING even on FreeBSD. Deprecate the DRV ones.

According to @asomers, libc should propagate the use of the portable constants `IFF_OACTIVE` and `IFF_RUNNING` for user-space applications, instead of `IFF_DRV_OACTIVE` and `IFF_DRV_RUNNING`. It least that's my understanding of [his comment](https://github.com/nix-rust/nix/pull/667#discussion_r152396984) in nix-rust/nix#667.

haiku: Add missing lutimes

* BeOS traditionally didn't have lutimes, however to make Haiku
  more compatible and easier to port for, we added an implementation
  of it.

Fix Fuchsia typos

Fix master CI

Apparently the most recently release broke three (!) platforms!

Apparently it fails on 1.23.0 for mysterious reasons

Looks like `cargo test` is now trying to test too many files due to
rust-lang/cargo#4750 so add a clause to the wrapper to ignore the bogus ones for
now