Expose unix ECN-related constants

I'm not certain of the correctness of the BSD definition, but I assume that's what CI's for.

add stdio constants for windows

A few useful constants for working with the stdio file descriptors.

I referenced the [msdn](https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/fileno?view=vs-2017) docs for the numbers, although I think 0,1,2 are standard  on most platforms for the stdio.

This reverts commit 0581f926.

This reverts commit 0dd7f2d1.

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.