rustix::pipe::fcntl_getpipe_size now returns the new size, which may be
greater than the requested size.
rustix::thread::FutexOperation and rustix::thread::futex are removed. Use
the functions in the rustix::thread::futex module instead.
rustix::process::waitpid's return type changed from WaitStatus to
(Pid, WaitStatus), to additionally return the pid of the child.
The SLAVE flag in rustix::mount::MountPropagationFlags is renamed
to DOWNSTREAM.
The "cc" feature is removed. It hasn't had any effect for several major releases.
All explicitly deprecated functions and types have been removed. Their deprecation messages will have identified alternatives.