Expose underline safe crate as part of an official target

[Urgau]

One thing that would be interesting, would be to expose a safe crate (rsix maybe ?) to all program that use our official target.

Something like extern crate rsix; at the top of the program would give programs access to (mostly) safe abstraction, avoiding the use for libc/nix, although they should work.

What is everyone take on that ?

[sunfishcode]

My first take here is that much of std has been designed with somewhat higher-level APIs which are more portable to Windows and other platforms, and that most general-purpose Rust code should ideally continue to use those APIs where applicable. As such, it seems ok that lower-level APIs aren't exposed by default.

However, one thing I don't know is that if std were to depend on rsix, and users separately depend on rsix, will we end up with two copies of rsix linked into programs? If so, it might be worth looking into what we could do to avoid that.

Another thing to consider is, what are the use cases? I'm tending to think in terms of starting with general-purpose Rust code that isn't specifically written for Mustang, however I'm interested in how others see Mustang being used in practice.

[bjorn3]

However, one thing I don't know is that if std were to depend on rsix, and users separately depend on rsix, will we end up with two copies of rsix linked into programs?

Yes, they will. The sysroot is compiled such that crates libstd depends on don't conflict with identical crates compiled by the user. They will just be both included.

[sunfishcode]

Ok. Well, rsix is pretty thin; most functions can be fully inlined, so maybe we can wait and see what the impact is when we get there.