Add infrastructure for compiletests

Also adds compilefail tests for some lints, closes #5646.

tests/compiletest/plugin/compile-fail/unrooted_must_root.rs

@@ -0,0 +1,27 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#![feature(plugin)]
+#![plugin(plugins)]
+#![allow(dead_code)]
+
+#[must_root]
+struct Foo {
+    v: i32
+}
+
+struct Bar {
+    f: Foo
+    //~^ ERROR Type must be rooted, use #[must_root] on the struct definition to propagate
+}
+
+fn foo1(_: Foo) {} //~ ERROR Type must be rooted
+
+
+fn foo2() -> Foo { //~ ERROR Type must be rooted
+    Foo { v: 10 }
+}
+
+
+fn main() {}