Fix {aarch64,arm}-android targets' CI

Android: Add VMADDR_ constants.

pthread_getattr_np is not present on illumos

Fix bootstrap on redox

Avoid attempting to enable the static_nobundle feature twice, which
results in rustc error E0636.

Add more constants for Linux like OS

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

Add SYS_pidfd_open and SYS_clone3

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

There was a missing period and the word "features" instead of "feature" in the section about `const extern fn`s.

In the `no-std` section of the README, there was a typo: "disable this feature remove the dependency". The word "to" was added in this commit to create "disable this feature to remove this dependency".

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

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

Add struct ip_mreqn to more Linux targets

Fix type definition for c_char on sparc-unknown-linux-gnu

Android: Add vsock constants and struct.

Add UIO_MAXIOV constant to uclibc

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`.

This will need corresponding changes in rust-lang/rust to activate, but
this will make it possible to make those changes.

Note that despite the apparent redundancy in config directives, the link
directives cannot be simplified any further. Attempting to factor out
the checks for `target_feature = "crt-static"` does not work.

Define some `sysconf` constants for WASI.

These syscalls were added recently, and therefore have consistent
numbers across different architetures (other than the weird offsetting
on some platforms).

!1880 added UIO_MAXIOV to libc, but did not add it to uclibc. This
causes build breaks for std against uclibc.