Oh good question! You're gonna get a long answer 😄

We have to do syscalls somewhere, which means that somewhere in our dependency tree, there'sunsafe. Either we useunsafe ourselves or we let some library do it for us.libc is used throughout the Rust ecosystem, even in the standard library. This also means that we are always usinglibc indirectly throughstd already. It is usually the recommended way to deal with low-level stuff, becauselibc standardizes behaviour across many platforms. However, that doesn't mean that we're stuck withlibc! We want to use as many safe abstractions overlibc as possible. Thenix crate, for example, provides safe APIs overlibc. We also (indirectly) userustix (a libc alternative). Wecould userelibc, but it only supports Linux and Redox at the moment.

Developing a libc alternative is definitely out of scope for this project, but we try to help out a bit with some of the projects I've mentioned when we need them.

Also note thatunsafe for FFI is the most acceptable form ofunsafe. Many of those APIs have no way they can cause unsound behaviour, it's just that the type system doesn't know about them. Still, using safe alternatives would of course be preferable.