Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

On sparc-unknown-linux-gnu, char is signed, not unsigned.

Support was previously added to gnu x86_64 and all musl targets but
others were not included because of a roundtrip issue [1].

This commit adds support for the ip_mreqn struct on all Linux GNU
targets which did not have the roundtrip issue.

[1]: https://github.com/rust-lang/libc/issues/1558



Signed-off-by: Bartel Sielski <bartel.sielski@gmail.com>

Move the link line for `libdl` up to `src/unix/mod.rs`, making it easier
to see all the libraries `libc` links to.

This also makes `libdl` respect `target-feature=+crt-static`.

The two library blocks that specify `#[link(name = "util")]` do not
actually reference any functions in `libutil`; the functions that do use
`libutil` don't have any reference to it. And having two library blocks
specify it results in two separate inclusions of `-lutil` on the linker
command line. Move the link lines up to `src/unix/mod.rs`, making it
easier to see all the libraries `libc` links to.

This also makes `libutil` respect `target-feature=+crt-static`.

Previously clock_getcpuclockid was enabled only on linux, with this
change it is enabled on all linux_like and freebsdlike.

The SIGCHLD variant of the siginfo structure also provides fields for
user and system time; expose those as well.

The first 3 fields of `siginfo_t` have different orders on MIPS. When
casting `siginfo_t` to a different type to access the fields of the
`sifields` union, avoid giving names to the first three fields, since
they're only present for memory layout and shouldn't be accessed from
the casted structure type.

On Linux, siginfo_t cannot expose these fields directly due to
https://github.com/rust-lang/libc/issues/716 , so expose them as
functions, just like si_addr and si_value.

In order to get alignment correct on both 32-bit and 64-bit
architectures, define an sifields union that includes a pointer field,
to ensure that it has the same alignment as a pointer.

Co-authored-by: Yuki Okushi <huyuumi.dev@gmail.com>

https://man7.org/linux/man-pages/man3/clock_getcpuclockid.3.html

In Linux we replaced VMADDR_CID_RESERVED with VMADDR_CID_LOCAL
in commit ef343b35d46667668a099655fca4a5b2e43a5dfe.
It is available since Linux v5.6, and it can be used to do
local communication if supported.

This patch deprecates VMADDR_CID_RESERVED for backward
compatibility.

Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>

This commit defines ETIMEDOUT, SIGSTKSZ, MINSIGSTKSZ

Reorganized some constants as well so they're grouped a bit better.

Co-Authored-By: Yuki Okushi <huyuumi.dev@gmail.com>

revenge of #598

Headers I used:

Oh, for reference, here are the headers I used while working on this:

- musl: https://git.musl-libc.org/cgit/musl/tree/include/regex.h?id=8327ae0cb23b799bc55a45e0d4bd95f5a2b1cdf1
- glibc: https://sourceware.org/git/?p=glibc.git;a=blob;f=posix/regex.h;h=87cce7f5cb8cc3b678467329b479bd511e250e61;hb=HEAD
- macOS: https://opensource.apple.com/source/Libc/Libc-997.90.3/include/regex.h.auto.html
- FreeBSD: https://github.com/freebsd/freebsd/blob/8103b0ddb041617b7cd161528f0ff93ff32970a2/include/regex.h
- NetBSD: https://github.com/NetBSD/src/blob/61c8f6fbb7e38b20e862d5cb3ed2203312963283/include/regex.h

This adds the defines from include/uapi/asm-generic/hugetlb_encode.h and the corresponding defines in include/uapi/linux/mman.h to linux_like/linux/gnu/mod.rs and the equivalent for musl in linux_like/linux/musl/mod.rs

Solves #1700

Removes two defines from musl/b32/hexagon.rs that are now provided two mudules "up"