Fix uname on FreeBSD

On FreeBSD, uname is an inline function.  The uname that is present in
libc.so is for FreeBSD 1.0 compatibility.  It expects a buffer of a
different size.

Fixes #1190
Reported-by: Alex Zepeda

On FreeBSD, uname is an inline function.  The uname that is present in
libc.so is for FreeBSD 1.0 compatibility.  It expects a buffer of a
different size.

Fixes #1190
Reported-by: Alex Zepeda

Bump version to 0.2.46

New release required for https://github.com/rust-lang/rust/pull/57121

Test out new bors integration

See if it works with Cirrus CI!

See if it works with Cirrus CI!

[skip ci] Add a Cirrus-ci.com build badge

Add IP_RECVDSTADDR on netbsd.

Accidentally left out IP_RECVDSTADDR on NetBSD in #1184

Reported-by: Alex Zepeda

Add IP_RECVIF to BSD and IP_RECVDSTADDR to apple.

FreeBSD/OpenBSD do not support IP_PKTINFO for IPv4 but use IP_RECVIF for interface index and IP_RECVDSTADDR for destination address.
NetBSD and macOS also support IP_RECVIF and IP_RECVDSTADDR in addition to IP_PKTINFO.
(For IPv6, all use IPV6_PKTINFO)

Define missing F_RDLCK, F_WRLCK and F_UNLCK constants on linux-mips -and s390x

These are defined in the fcntl.h glibc header on MIPS and s390x
systems on Linux but missing in the libc crate, so add them as they
are required for the file locking API in rustc.

These are defined in the fcntl.h glibc header on s390x systems
on Linux but missing in the libc crate, so add them as they are
required for the file locking API in rustc.

These are defined in the fcntl.h glibc header on MIPS systems
on Linux but missing in the libc crate, so add them as they are
required for the file locking API in rustc.

make tm struct members public

This PR makes the members of `struct tm` public.

I see no reason why these fields should not be public fields. They are public in the other targets. I did a blame and it seems that they have been private since added a couple years ago.

https://github.com/rust-lang/libc/commit/53e0d387f8765e9faa1ea921450167bb7f0b31ff

add some socket functions and a SOCKET type for windows

This PR adds a few of the socket functions for windows. Some targets use the `stdcall` calling convention for these functions, so I put them in an `extern "system"` block ([see the nomicon](https://doc.rust-lang.org/nomicon/ffi.html#foreign-calling-conventions)).

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