Q:

How can one detect the OS type using Rust?

How can one detect the OS type using Rust? I need to specify a default path specific to the OS. Should one use conditional compilation?
For example: 
#[cfg(target_os = "macos")]
static DEFAULT_PATH: &str = "path2";
#[cfg(target_os = "linux")]
static DEFAULT_PATH: &str = "path0";
#[cfg(target_os = "windows")]
static DEFAULT_PATH: &str = "path1";

A:

You can also use cfg! syntax extension.
if cfg!(windows) {
    println!("this is windows");
} else if cfg!(unix) {
    println!("this is unix alike");
}

A:

It's a little late, but there's a builtin way to detect the OS using the std lib. Eg:
use std::env;

println!("{}", env::consts::OS); // Prints the current OS.

The possible values are described here
Hope this help somebody in the future.

A:

EDIT: 
Since writing this answer, it seems the author of the os_type crate has retracted functionality that exposed OSes like Windows. Conditional compilation is probably your best bet here -- os_type only seems to detect Linux distributions now, judging from its lib.rs.

ORIGINAL ANSWER:
You could always use the os_type crate. From the front page:
extern crate os_type;

fn foo() {
      match os_type::current_platform() {
        os_type::OSType::OSX => /*Do something here*/,
        _ => None
    }
}

