Add test for sensible #[start] error message.

Fixes #9575.

src/test/compile-fail/issue-9575.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.
+
+#[start]
+fn start(argc: int, argv: **u8, crate_map: *u8) -> int {
+    //~^ ERROR start function expects type: `fn(int, **u8) -> int`
+    0
+}