This incorporates the changes needed to cross-compile `rustc` for the
aarch64-apple-darwin target.

Revive CI for the switch target

Expose EPOLLEXCLUSIVE on illumos platform

Initially the EPOLLEXCLUSIVE definition was hidden on the illumos
platform as it lacked explicit support.  After further review, it was
concluded that EPOLLEXCLUSIVE can safely be considered a no-op, when not
fully implemented by the OS, making it safe for use on illumos.

openbsd: Fix `WIFSTOPPED` following upstream

https://github.com/openbsd/src/blob/b66614995ab119f75167daaa7755b34001836821/sys/sys/wait.h#L52

Limit macOS `$INODE64` symbol names to x86 and x86_64

The new ARM-based platform doesn't need these as there's no legacy
constraints.

Tested via

**demo.c**

```c

int main() {
  fstat(0, NULL);
  fstatat(0, NULL, NULL, 0);
  lstat(NULL, NULL);
  stat(NULL, NULL);
  readdir(NULL);
  readdir_r(NULL, NULL, NULL);
}
```

**Compilation**

```none
% SDKROOT=/Applications/Xcode-beta.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX11.0.sdk MACOSX_DEPLOYMENT_TARGET=11.5 cc -arch arm64 demo.c

% nm a.out
0000000100008030 d __dyld_private
0000000100000000 T __mh_execute_header
                 U _fstat
                 U _fstatat
                 U _lstat
0000000100003e64 T _main
                 U _readdir
                 U _readdir_r
                 U _stat
                 U dyld_stub_binder
```

This has also been experimentally compiled on a Developer Transition Kit.

Bump version ready to import into Android tree.

Fixes #1775

Update emsdk version

Add more WASI libc definitions.

This adds various WASI libc definitions to the Rust libc bindings that I
needed while porting some applications to WASI.

It also removes the `pause` binding since newer versions of WASI libc
have removed this function as well. (WASI currently has no syscall with
this functionality.)

https://reviews.freebsd.org/rS357382

Plus, add new constants for sysctls that give names to existing magic numbers.

https://reviews.freebsd.org/rS350749
https://reviews.freebsd.org/rS352486

It was picked up transitively on >10, but tests failed on 10

Wide chars are unsigned when normal chars are

sys/stat.h is a machine-independent header, but it has ifdefs for i386.
The version that was called x86_64.rs should be used on powerpc64 too,
but I don't have a machine to test that on.

I just got 'libxul.so: Undefined symbol "mq_close"' when rebuilding Firefox..
How did no one catch this before??

This is correct for both FreeBSD and DragonFly:
https://github.com/freebsd/freebsd/blob/master/lib/librt/Symbol.map
https://github.com/DragonFlyBSD/DragonFlyBSD/blob/e7ab884bd49753f8884eb597d10d6569a08fa0df/lib/librt/mq.c
https://github.com/DragonFlyBSD/DragonFlyBSD/blob/e7ab884bd49753f8884eb597d10d6569a08fa0df/lib/librt/aio.c

Disable tests for the switch target, for now

Add missing sysconf constants for Haiku

Hi,

Could you add some missing Haiku constants (i'm guessing they were added after Haiku port was last updated)?

These are defined in `unistd.h`: https://github.com/haiku/haiku/blob/194a45c6b4183083afdc7fac7b9e85f9162cdeb2/headers/posix/unistd.h#L134-L137

Add ucontext_t/mcontext_t for aarch64 Android

Fix ordering of allowed lints