ci: switch to the rust-lang-ci-mirrors bucket for mirrors

Previously mirrors were stored in the rust-lang-ci2 bucket, which is
meant to store temporary data (the CI artifacts). This switches the code
to fetch from the new mirrors bucket.

The old files won't be removed, but they won't be backed up either.

r? @gnzlbg

Previously mirrors were stored in the rust-lang-ci2 bucket, which is
meant to store temporary data (the CI artifacts). This switches the code
to fetch from the new mirrors bucket.

The old files won't be removed, but they won't be backed up either.

Revert breaking musl change

This reverts commit 9df2deb3.

Adding UTIME_NOW and UTIME_OMIT to OSes which support utimensat

I've managed to verify a handful of these:

- [FreeBSD](https://github.com/freebsd/freebsd/blob/1d6e4247415d264485ee94b59fdbc12e0c566fd0/tools/build/stat.h#L35)
- [NetBSD](https://github.com/NetBSD/src/blob/64b8a48e1288eb3902ed73113d157af50b2ec596/sys/sys/stat.h#L235)
 - [Apple](https://opensource.apple.com/source/xnu/xnu-4903.221.2/bsd/sys/stat.h.auto.html)

I'm less confident in these:
 - [Haiku](https://github.com/haiku/haiku/blob/abb59d7351c7ddb50c63c40430a82d94fa61917a/headers/posix/sys/stat.h#L105)
   - I could be wrong on this one: https://github.com/haiku/haiku/search?q=UTIME_NOW&unscoped_q=UTIME_NOW
 - [WASI](https://github.com/CraneStation/wasi-libc/blob/24792713d7e31cf593d7e19b943ef0c3aa26ef63/libc-top-half/musl/include/sys/stat.h#L71)
  - I could be wrong on this one: https://github.com/CraneStation/wasi-libc/search?q=UTIME_NOW&unscoped_q=UTIME_NOW
 - [Solarish](https://github.com/illumos/illumos-gate/blob/4e0c5eff9af325c80994e9527b7cb8b3a1ffd1d4/usr/src/uts/common/sys/stat.h#L478)

Some update for vxWorks

This is to address issues:
rust-lang#1469 and rust-random/getrandom#86 (comment)

What have been changed in this PR:

 1. adding randBytes(), randABytes(), randUBytes(), randSecure() and taskDelay()
 2. change armv7-wrs-vxworks to armv7-wrs-vxworks-eabihf
 3. code cleanup

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 spurious extra line

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

Adding OpenBSD as per request, verified here: https://github.com/openbsd/src/blob/master/sys/sys/stat.h#L188

Remove unnecessary trailing semi-colon

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

code cleanup and adding randBytes() etc

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.

2. change armv7-wrs-vxworks to armv7-wrs-vxworks-eabihf
3. code cleanup

add support for sparc64 on OpenBSD