Add regression test

Author: jseyfried

src/test/compile-fail/macro-expanded-include/foo/mod.rs

@@ -13,3 +13,7 @@
 macro_rules! m {
     () => { include!("file.txt"); }
 }
+
+macro_rules! n {
+    () => { unsafe { asm!(include_str!("file.txt")); } }
+}

src/test/compile-fail/macro-expanded-include/test.rs

@@ -8,12 +8,14 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![feature(rustc_attrs)]
+#![feature(asm, rustc_attrs)]
+#![allow(unused)]
 
 #[macro_use]
 mod foo;
 
 m!();
+fn f() { n!(); }
 
 #[rustc_error]
 fn main() {} //~ ERROR compilation successful