Add a test for deprecated phase(syntax)

Author: Keegan McAllister

src/test/run-pass/deprecated-phase-syntax.rs

@@ -0,0 +1,19 @@
+// Copyright 2013-2014 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.
+
+#![feature(phase)]
+
+//~ WARNING phase(syntax) is a deprecated synonym for phase(plugin)
+#[phase(syntax, link)]
+extern crate log;
+
+fn main() {
+    debug!("foo");
+}