Fix kqueue filter consts type on NetBSD [WAS: Provide EV_SET]

Using BSD kqueue's `kevent` structure is tedious, because some BSD variants define the structure slightly differently. This forces user's code to differentiate between BSD variants and initialize `kevent` accordingly, which is annoying and error-prone.

For an example, refer to [MIO](https://github.com/carllerche/mio/blob/master/src/sys/unix/kqueue.rs#L38).

This is an attempt to fix it - provide a ctor function with the same signature across BSD variants.

Is an `impl` piece for a C structure allowed in libc?

**edit:** I noticed the `kevent` function has a similar problem, maybe I should include a fix for that too...
**edit:** ^ Done

fix ABI breakage in syscall constants

Fix other platforms impacted by 9029cfb9

Initial fixes for linux x32

Tested with a local build of rustc. The main test can be compiled but fails to execute (receives SIGTRAP, which I think in this case indicates memory violation, I will open an issue in the rustc repo).

This PR is important because it fixes the definition of `c_long` and `c_ulong`. Without these fixes, rustc crash with the error:

```
Cannot emit physreg copy instruction
UNREACHABLE executed at /checkout/src/llvm/lib/Target/X86/X86InstrInfo.cpp:5778!
```

Related https://github.com/rust-lang/rust/issues/37976

SYS_* constants are of type long in Android

The SYS_* constants should be `c_long` as `syscall` expect a `c_long` as first argument and in Android headers, there is no sign that these constants should be `unsigned long`.

So the compilation targeting ARM Android fails for dependent crates using `syscall`.

Introduce pthread_cancel() for terminating threads

pthread_cancel() is safer way to terminate thread than pthread_kill().

This function can be found from ISO/IEC 9945-1:1996 (“POSIX.1”) and first introduced into Single Unix Specification version 2 on 1997.

add setfsgid/setfsuid on Linux

Add BOTHER & termios2 to Android & Linux

This should be the same for both the struct and the constant across all Linux/Android platforms, but we'll see!

Error was "bad pthread_cancel function pointer: rust: 8362822 (0x7f9b46) != c 8358779 (0x7f8b7b)"

Note that termios2 doesn't exist on powerpc(64), termios
is used instead.

Add more Linux-based syscall tables

* Add syscall tables to most remaining arches in `src/unix/notbsd`
* Add aarch64/arm musl to CI
* Update dependencies

* Add syscall tables to most remaining arches in `src/unix/notbsd`
* Add aarch64/arm musl to CI
* Update dependencies

pthread_cancel() is safer way to terminate thread than pthread_kill().

This function can be found from ISO/IEC 9945-1:1996 (“POSIX.1”) and
first introduced into Single Unix Specification version 2 on 1997.

Local peer credential support for FreeBSD.

FreeBSD uses SOL_SOCKET/LOCAL_PEERCRED instead of SOL_SOCKET/SO_PEERCRED parameters to getsocktopt to retrieve the credentials of a socket's peer.

(Documented in man 4 unix)

Add missing powerpc64 in musl/mod.rs

powerpc64 was missing in musl/mod.rs and making build fail
as it was not able to find types, like c_char.

powerpc64 was missing in musl/mod.rs and making build fail
as it was not able to find types, like c_char.

Local peer credential support for Darwin.

Darwin uses SOL_LOCAL/LOCAL_PEERCRED instead of SOL_SOCKET/SO_PEERCRED parameters to getsocktopt to retrieve the credentials of a socket's peer.

(Documented in man 4 unix)

define SYS_renameat2 + flags on linux

Motivation: there is no glibc wrapper for this syscall

Motivation: there is no glibc wrapper for this syscall

Add getprotobynumber

Add `project_name` attribute to appveyor badge.

There was a recent [issue](https://github.com/rust-lang/crates.io/issues/587) in crates.io where appveyor is looking for a dash separated URL for the link to appveyors site:
```
https://ci.appveyor.com/project/rust-lang-libs/libc
```
 and the actual repo name for the image badge url:
```
https://ci.appveyor.com/api/projects/status/github/rust-lang/libc?svg=true
```
We recently added the ability to specify a `project_name` that fixes this issue.  You'll notice that currently on https://crates.io/crates/libc the appveyor badge on the right sidebar show `build unknown`, this PR will address that issue.

Please let me know if you have any questions.