Define newlib socket types by target arch

This is a follow-up to https://github.com/rust-lang/libc/pull/1477. As mentioned in that PR, the primary (only?) users of these newlib definitions are myself and @leo60228. This PR makes it so that my arm-based 3DS target keeps using the old socket definitions while leo's aarch64-based Switch target uses the BSD versions.

The 3DS also has inverted definitions for `POLLHUP` and `POLLOUT` for whatever reason, so I figured I'd take care of that here too.

several const ioctl() BPF aren't defined on OpenBSD

unbreak OpenBSD after #1448

Remove invalid Fuchsia functions

Extension of #1468

These functions are not present in Fuchsia's libc, so they cannot be
used in a program today. If Fuchsia ever decides to add these functions
to their libc, they can be added back as necessary.

These files were generated in the following manner:

1. Create a list of the current functions in Fuchsia's libc, put in `rust-functions.txt`
2. Change directory into [`fuchsia/zircon/third_party/ulib/musl/include`](https://fuchsia.googlesource.com/fuchsia/+/master/zircon/third_party/ulib/musl/include/)
3. Run a script to determine which symbols in `rust-functions.txt` are not in the include dir:
    ```bash
    for i in $(cat rust-functions.txt);
        if ! rg $i > /dev/null; then
            echo $i
        fi
    done
    ```
4. This produces [a list of 99 functions](https://github.com/rust-lang/libc/pull/1468#issuecomment-521777743), which are then removed from this crate.

Add sys/termios.h support for Redox

Add constants for termios on Redox.

cc @jackpot51

Add musl support for MIPS64 & bump to 0.2.63

Tested with patched stage2; both static and dynamic binaries confirmed working.

Initial CI support in the form of no-core targets are added.

Add ioctl() constants for BPF

Update newlib socket types to FreeBSD

None

Rename armv7-wrs-vxworks target

Remove unnecessary trailing semi-colon

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

These fuctions are not present in Fuchsia's libc, so they cannot be
used in a program today. If Fuchsia ever decides to add these functions
to their libc, they can be added back as necessary.

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