Merge pull request #915 from Manishearth/sysroot

Use rustc --print sysroot, bump to v66 r? @llogiq

Author: llogiq

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "clippy"
-version = "0.0.65"
+version = "0.0.66"
 authors = [
 	"Manish Goregaokar <manishsmail@gmail.com>",
 	"Andre Bogus <bogusandre@gmail.com>",

src/lib.rs

@@ -17,6 +17,7 @@ use rustc::session::{config, Session};
 use rustc::session::config::{Input, ErrorOutputType};
 use syntax::diagnostics;
 use std::path::PathBuf;
+use std::process::Command;
 
 struct ClippyCompilerCalls(RustcDefaultCalls);
 
@@ -109,9 +110,14 @@ pub fn main() {
     let toolchain = option_env!("RUSTUP_TOOLCHAIN").or(option_env!("MULTIRUST_TOOLCHAIN"));
     let sys_root = match (home, toolchain) {
         (Some(home), Some(toolchain)) => format!("{}/toolchains/{}", home, toolchain),
-        _ => option_env!("SYSROOT")
-                .expect("need to specify SYSROOT env var during clippy compilation, or use rustup or multirust")
-                .to_owned(),
+        _ => option_env!("SYSROOT").map(|s| s.to_owned())
+                                   .or(Command::new("rustc").arg("--print")
+                                                            .arg("sysroot")
+                                                            .output().ok()
+                                                            .and_then(|out| String::from_utf8(out.stdout).ok())
+                                                            .map(|s| s.trim().to_owned())
+                                                            )
+                .expect("need to specify SYSROOT env var during clippy compilation, or use rustup or multirust"),
     };
 
     if let Some("clippy") = std::env::args().nth(1).as_ref().map(AsRef::as_ref) {