More precise identification of Redox target

[jackpot51]

This is a minor change to match the way that the libc and rand crates now have checking for Redox. It is more accurate than checking for cfg(redox).

[jackpot51]

Either this, or a change adding "redox" to https://github.com/rust-lang/rust/blob/master/src/librustc/session/config.rs#L959 need to be done to fix building on Redox.

I would prefer not to modify the compiler :-/

[eddyb]

It's surprising to me that redox doesn't behave like other unices here. Should be at least documented.

[jackpot51]

@eddyb Redox is not a Unix. It is Unix-like in the sense that it has very similar system calls, a similar filesystem, and similar methodology but it does not include a POSIX compatible C library - all system calls are accessed from a Rust crate called redox_syscall

[eddyb]

Interesting - would libstd have to depend on such a library?

[jackpot51]

Yes, I believe so. I have not found the cleanest way to do this yet, but would love to have input into it. I am building a Redox std::sys here: https://github.com/redox-os/rust/tree/redox/src/libstd/sys/redox

At the moment, I am exporting redox_syscall from a custom libc to get around this issue.