Use rustix instead of libc

[swsnr]

rustix provides safe alternatives to everything we do with libc and
lets us get rid of a bunch of weird code.

[daniestevez]

rustix's memfd_create implementation uses some magic to call the libc function if present or perform a syscall if not. So it seems that this will solve the problems I described in #22, which is great news.

[swsnr]

I thought rustix doesn't use libc at all unless the use-libc feature was set?

In any case, it doesn't work, so don't have your hopes too high. For some reason sending the FD over an unconnected socket returns EINVAL 🤷, hence the test failure. Haven't had time to take a closer look yet.

[daniestevez]

I thought rustix doesn't use libc at all unless the use-libc feature was set?

I was reading the #[cfg]'s in lib.rs wrong. By default it uses the linux_raw backed, as the documentation says.

[swsnr]

Blocked on bytecodealliance/rustix#884

[swsnr]

Released as 2.1.0, thanks to the very very fast fix by the rustix maintainers. Thanks @sunfishcode 👏🏿

[daniestevez]

Thank you! I have tested this new release in my embedded platform with an old glibc and it works perfectly. I can now continue using an unmodified version of this crate.

[swsnr]

Your welcome. It's just coincidental though; I just wanted to get rid of all the unsafe code 🙂