Bring the MUSL version of siginfo_t up-to-date.

**Background**

As far as I can tell, the [current MUSL version of `siginfo_t`](https://git.musl-libc.org/cgit/musl/tree/include/signal.h#n97) includes fields like [`si_pid`](https://git.musl-libc.org/cgit/musl/tree/include/signal.h#n108) and [`si_uid`](https://git.musl-libc.org/cgit/musl/tree/include/signal.h#n109).

**Change**

This update unifies `siginfo_t` support between GNU and MUSL.

Unpin the `cc` crate version

Fixes #1933

Add constants of socket options

Signed-off-by: Kenta Tada <Kenta.Tada@sony.com>

Signed-off-by: Kenta Tada <Kenta.Tada@sony.com>

Add issue templates with new style

Add lockf() operations to Android

Reference:
https://github.com/aosp-mirror/platform_bionic/blob/master/libc/include/bits/lockf.h#L39-L46

Reference:
https://github.com/aosp-mirror/platform_bionic/blob/master/libc/include/bits/lockf.h#L39-L46

Rollup of 3 pull requests

Successful merges:

 - #1943 (Add definitions for Linux debug related MAGIC)
 - #1944 (Include sendfile64() for Linux)
 - #1945 (Disable libc-test for MIPS64 for now)

Failed merges:

r? `@ghost`

Disable libc-test for MIPS64 for now

Include sendfile64() for Linux

`sendfile` uses the `off_t` type, which is platform dependent. On 64-bit architectures, I can pass an `off64_t` as the third argument to `libc::sendfile`, but on 32-bit architectures, this does not compile. `sendfile64` on the other hand uses a 64-bit wide offset even on 32-bit architectures, so that `off64_t` can be used.

Excerpt from `man 2 sendfile`:

> The original Linux sendfile() system call was not designed to handle large file offsets. Consequently, Linux 2.4 added sendfile64(), with a wider type for the offset argument.

I hope that supporting Linux versions below 2.4 is not a requirement for libc.

Add definitions for Linux debug related MAGIC

This commit adds definitions for Linux debug related MAGIC to confirm if the filesystem for debug is mounted.

Signed-off-by: Kenta Tada <Kenta.Tada@sony.com>

Signed-off-by: Kenta Tada <Kenta.Tada@sony.com>

Revive `sparc-unknown-linux-gnu` CI

cc rust-lang/rust#58564

Add some more targets for build testing

- `x86_64-unknown-illumos`: We now have the illumos module and it'd be great if we could test it actually.
- `aarch64-apple-darwin`: This target will be used more widely in the future and it should make sense to run CI for it as well.

Run build test for `x86_64-unknown-redox`

Fix #1457

Android: Add preadv and pwritev.

From sys/uio.h. Note that preadv64/pwritev64 are already included in
src/unix/linux_like/mod.rs.

Add freebsd nmount

Adding FreeBSD's nmount call to mount devices on filesystems.  nmount is preferred over mount.

Drop FreeBSD 10 and add FreeBSD 13 image on Cirrus CI

This should fix our CI.

From sys/uio.h. Note that preadv64/pwritev64 are already included in
src/unix/linux_like/mod.rs.
Also fix parameter names of process_vm_[readv,writev] to match Bionic
header.

Revive `powerpc-unknown-linux-gnu` CI

Fix #1425