From 651bb69ecd82cc58aa7d967563784e989fab7873 Mon Sep 17 00:00:00 2001
From: Alex Crichton <alex@alexcrichton.com>
Date: Thu, 13 Oct 2016 12:01:59 -0700
Subject: [PATCH] rustbuild: Less panics in musl_root

Don't panic if the target wasn't configured.
---
 src/bootstrap/lib.rs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/bootstrap/lib.rs b/src/bootstrap/lib.rs
index 12938b8326e79..30983869c2e3b 100644
--- a/src/bootstrap/lib.rs
+++ b/src/bootstrap/lib.rs
@@ -991,7 +991,8 @@ impl Build {
 
     /// Returns the "musl root" for this `target`, if defined
     fn musl_root(&self, target: &str) -> Option<&Path> {
-        self.config.target_config[target].musl_root.as_ref()
+        self.config.target_config.get(target)
+            .and_then(|t| t.musl_root.as_ref())
             .or(self.config.musl_root.as_ref())
             .map(|p| &**p)
     }