auto merge of #14517 : lucy/rust/issue-14499, r=alexcrichton

Fixes #8537
Fixes #14499 (duplicate of #8537)

Old:
```rust
test.rs:2 	pub extern "xxxxx" fn add(x: int, y: int) -> int {
          	                   ^~
```

New:
```rust
test.rs:2 	pub extern "xxxxx" fn add(x: int, y: int) -> int {
          	           ^~~~~~~
```

src/test/compile-fail/issue-8537.rs

@@ -0,0 +1,15 @@
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+pub extern
+  "invalid-abi" //~ ERROR illegal ABI
+fn foo() {}
+
+fn main() {}