This reverts commit 89e8ae6a.

These changes bring the types up to parity with recent Emscripten
versions using the upstream LLVM wasm backend. These changes should be
coordinated with the upgrade of rustc's Emscripten support. See
https://internals.rust-lang.org/t/upgrading-rust-s-emscripten-support/10684

Remove unnecessary trailing semi-colon

libc currently denies all warnings by default. This commit denies
warnings only when libc is built in CI.

add support for sparc64 on OpenBSD

Fix FreeBSD

#1440 broke FreeBSD by changing `libc` FreeBSD targets to require a `cfg(freebsdXX)` to be defined, but not updating `build.rs` to define `freebsd11` when `LIBC_CI` is not available. Since `LIBC_CI` is always defined on CI, this issue went undetected.

This PR fixes that issue in the `build.rs` and introduces a build task that tests FreeBSD without `LIBC_CI` on FreeBSD11, although I'm  not sure this would have caught the issue in #1466 .

Closes #1466 .

Update links

Update README Azure badge to rust-lang2 org

Bump version to 0.2.61

Releasing a version now will allow Redox compilation to work again, as it will include #1438

Add support for FreeBSD CURRENT (aka freebsd13)

Using the last FreeBSD-CURRENT (development snapshot) the libc build, but tests fail.
This patch detects and supports FreeBSD CURRENT as freebsd13, and reworks the conditional compilation to use the `freebsd11` attribute instead of `not(freebsd12)`
For now, freebsd13 is reusing all freebsd12 definitions, except for `ELAST`
While here, add a new `errno`introduced in freebsd13

Move musl-compatible constants to linux/mod.rs

This is a continuation of #1452. I think CI is ready to run fully and the PR is ready to be merged if the pipelines pass based on the CI I've done using musl libc in my own projects.

Support Vxworks

Define the C interface to VxWorks

Define the C interface to vxWorks for x86, x86_64, ARM, ARM 64-bit, PowerPC, PowerPC SPE and PowerPC 64-bit.

Upgrade FreeBSD's CI image to release 11.3

skip roundtrip on few structs on OpenBSD

skip roundtrip on some structs on OpenBSD. it is mostly the same than other targets: dirent, utsname, utmp.

define KERN_TIMEOUT_STATS and incr KERN_MAXID on OpenBSD

`KERN_TIMEOUT_STATS` has been defined in [sys/sysctl.h (1.194)](https://cvsweb.openbsd.org/cgi-bin/cvsweb/src/sys/sys/sysctl.h?rev=1.194&content-type=text/x-cvsweb-markup)

Add IP_RECVERR (unix/linux_like/mod.rs)

Setup Azure Pipelines

cc @alexcrichton this needs enabling Azure Pipelines for this repo

The 11.3-release GCE image isn't working due to a bug in the included
py36-google-compute-engine package, but that bug is fixed in the latest
stable/11 images.