Constants for the linux nfqueue netlink protocol (userspace firewall).

Continuation of #1562 and #1571.

This triggers a warning on a recent nightly, which in turn breaks CI due to
`#![deny(warnings)]` in libc-test/build.rs

This commit performs a number of updates for libc with the `wasm32-wasi`
target:

* Updates the `wasi-libc` repository commit used (previously known as
  `wasi-sysroot`)
* Updates the container to Ubuntu 19.10 which has Clang 9 packaged which
  is all we need.
* Avoids building `wasmtime` and instead downloads a precompiled binary.
* Updates bindings in `src/wasi.rs` to match the current upstream state.

Modelled after the cmsg tests, this wraps the C macro into a function, and then
compares the results to the Rust implementation in libc.

sock_extended_err is a struct returned as a control message when the sockopt
IP_RECVERR is set, when recvmsg has the MSG_ERRQUEUE flag set.  IP_RECVERR and
MSG_ERRQUEUE are constants both already defined here.

This moves the linux/ headers after others
This keeps the Android tests closer to the Linux ones.
I think this is needed to get linux/errqueue.h to not cause compilation
failures.

Co-Authored-By: gnzlbg <gnzlbg@users.noreply.github.com>

Signed-off-by: patrick felt <patrick.felt@sling.com>

initial work from @landryb for OpenBSD, various fixes and NetBSD support from me.

Fixes #1585

Signed-off-by: Arthur Gautier <baloo@gandi.net>

Signed-off-by: Arthur Gautier <baloo@gandi.net>

First batch for #1562

This adds libc-test support for Freebsd10 and a CI build job that tests
FreeBSD10 with LIBC_CI only.

Currently, libc supports and detects freebsd11 and freebsd13
Unknown versions, like freebsd13, is treated as freebsd11.
This patch solve the issues, detecting freebsd13 and treating it like
freebsd12.
Inverting the logic not(freebsd12) -> freebsd11 where possible