add signal and raise bindings for windows

This PR adds `signal` and `raise` bindings for windows.

I don't know these functions or linux very well, so I leaned on other overrides of signal in the linux bindings, and the [cppreference page](https://en.cppreference.com/w/cpp/header/csignal) for adding the bindings.

I added some constants that were shown on the [microsoft signal page](https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/signal?view=vs-2017) and used the default values I found spelunking through my own copy of `signal.h` that came along with visual studio.

The automated tests pass and my toy apps use the `signal` and `raise` as expected. Let me know if there is anything else I need to do, or any extra tests to write.

EDIT:
currently working on getting a nice isolated msys2 environment I can use to dev against.
- [x] msys2 env setup and building

Add `AI_*` constants from `netdb.h` for macOS.

separate for gnu and msvc


scope resolve c_int

these types are not allowed, and more scope resolution


use size_t

Add MFD_HUGETLB const for linux

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>

Fix for rust-lang/rust issue #50583

Fix build on x86_64-unknown-cloudabi, bump version

Add support for SysV semaphores on Apple platform

Move FreeBSD testing from Travis/QEMU to Cirrus-CI

Fixes #1163

Move SOL_BLUETOOTH to notbsd module

https://github.com/torvalds/linux/blob/master/include/linux/socket.h#L334
https://android.googlesource.com/platform/bionic/+/master/libc/include/sys/socket.h#283
https://git.musl-libc.org/cgit/musl/tree/include/sys/socket.h#n259

Seems like it should be okay for a broader exposure than `linux::other`. Maybe I am missing something.

Don't submit build status to buildbot.rust-lang.org

That service no longer exists.

That service no longer exists.

Fixes #1163

define `TIMER_ABSTIME` on BSD

musl: 64-bit: Ensure proper (c)msghdr layout on big-endian

Discovered while debugging: djg/audioipc-2#52

Added setegid function

Adding the `setegid` function to libc. I had a look and this is in Apple, Linux and Fuchsia so I'm hoping it works for all the BSDs etc. But if anything fails in CI I'll change it accordingly.

NetBSD: unbreak tests; neither TCP_NOPUSH or TCP_NOOPT yet exist here

Discovered while debugging: djg/audioipc-2#52

Add AF_XDP, PF_XDP and SOL_XDP consts for linux

These are needed to work with `AF_XDP` sockets, see https://www.kernel.org/doc/html/v4.19/networking/af_xdp.html

DragonflyBSD: add ENOMEDIUM and EASYNC

These errno's are defined in <sys/errno.h> on DragonFlyBSD.

Signed-off-by: Levente Kurusa <lkurusa@acm.org>

These errno's are defined in <sys/errno.h> on DragonFlyBSD.

Signed-off-by: Levente Kurusa <lkurusa@acm.org>

Add SO_PASSCRED for sparc64

Needed to get `nix` up and running on `sparc64-unknown-linux-gnu`