Add static_recursion feature gate.

src/test/compile-fail/static-recursion-gate.rs

@@ -0,0 +1,16 @@
+// Copyright 2015 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 mut S: *const u8 = unsafe { &S as *const *const u8 as *const u8 };
+//~^ ERROR recursive static
+
+pub fn main() {
+    unsafe { assert_eq!(S, *(S as *const *const u8)); }
+}

src/test/run-pass/static-recursive.rs

@@ -8,6 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+#![feature(static_recursion)]
+
 static mut S: *const u8 = unsafe { &S as *const *const u8 as *const u8 };
 
 pub fn main() {