Port vsock-rs to use rustix

vsock-rs currently uses a mix of nix and libc to handle
the underlying system calls. However, in addition to adding
a few extra dependencies, this means that there is a significant
amount of unneeded unsafe code in the project.

By porting to "rustix", we gain the following advantages:

- Most of the code in the project can be rewritten completely
  safely.
- We avoid going through libc. In other projects this has been
  benchmarked to lead to a 2.5% performance increase.
- On Linux, we reduce the number of dependencies the project
  pulls in. On other platforms, it stays the same.

Blocked on bytecodealliance/rustix#1558

Signed-off-by: John Nunley <[email protected]>

Author: notgull

Cargo.toml

@@ -11,8 +11,7 @@ edition = "2021"
 exclude = ["test_fixture"]
 
 [dependencies]
-libc = "0.2.158"
-nix = { version = "0.30.1", features = ["ioctl", "socket"] }
+rustix = { git = "https://github.com/forkgull/rustix", branch = "notgull/vsock", default-features = false, features = ["std", "net"] }
 
 [dev-dependencies]
 rand = "0.9.0"