Expand string literals and exprs inside of macros

A couple of syntax extensions manually expanded expressions, but it
wasn't done universally, most noticably inside of asm!().

There's also a bit of random cleanup.

src/test/run-pass/asm-concat-src.rs

@@ -0,0 +1,16 @@
+// 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.
+
+// ignore-fast #[feature] doesn't work with check-fast
+#[feature(asm)];
+
+pub fn main() {
+    unsafe { asm!(concat!("", "")) };
+}

src/test/run-pass/asm-out-assign.rs

@@ -1,4 +1,4 @@
-// Copyright 2012-2013-2014 The Rust Project Developers. See the COPYRIGHT
+// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
 // file at the top-level directory of this distribution and at
 // http://rust-lang.org/COPYRIGHT.
 //

src/test/run-pass/ext-expand-inner-exprs.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.
+
+static FOO : &'static [u8] = bytes!(concat!(concat!("hel", "lo"), "world"));
+
+pub fn main() {
+    assert_eq!(FOO, "helloworld".as_bytes());
+}