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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.