From 4e7d7c7cd832dd7fee4568a0e81c519af53c8769 Mon Sep 17 00:00:00 2001
From: Jorge Aparicio <japaricious@gmail.com>
Date: Mon, 3 Oct 2016 09:12:13 -0500
Subject: [PATCH] bump rustc-cfg version and show a better error message when
 it fails

---
 library/compiler-builtins/Cargo.toml | 2 +-
 library/compiler-builtins/build.rs   | 8 ++++++--
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/library/compiler-builtins/Cargo.toml b/library/compiler-builtins/Cargo.toml
index 93f7d1970125..c198d9f3ccb6 100644
--- a/library/compiler-builtins/Cargo.toml
+++ b/library/compiler-builtins/Cargo.toml
@@ -6,7 +6,7 @@ version = "0.1.0"
 
 [build-dependencies]
 gcc = "0.3.35"
-rustc-cfg = "0.1.2"
+rustc-cfg = "0.2.0"
 
 [dependencies]
 
diff --git a/library/compiler-builtins/build.rs b/library/compiler-builtins/build.rs
index a05a1a590ad2..cf9a24e3b1f7 100644
--- a/library/compiler-builtins/build.rs
+++ b/library/compiler-builtins/build.rs
@@ -2,8 +2,9 @@ extern crate gcc;
 extern crate rustc_cfg;
 
 use std::collections::BTreeMap;
-use std::env;
+use std::io::Write;
 use std::path::Path;
+use std::{env, io, process};
 
 use rustc_cfg::Cfg;
 
@@ -50,7 +51,10 @@ fn main() {
 
     let target = env::var("TARGET").unwrap();
     let Cfg { ref target_arch, ref target_os, ref target_env, ref target_vendor, .. } =
-        Cfg::new(&target).unwrap();
+        Cfg::new(&target).unwrap_or_else(|e| {
+            writeln!(io::stderr(), "{}", e).ok();
+            process::exit(1)
+        });
     // NOTE we are going to assume that llvm-target, what determines our codegen option, matches the
     // target triple. This is usually correct for our built-in targets but can break in presence of
     // custom targets, which can have arbitrary names.