Add missing #![feature(rustc_private)] annotation

src/libfmt_macros/lib.rs

@@ -11,6 +11,7 @@
        test(attr(deny(warnings))))]
 
 #![feature(nll)]
+#![feature(rustc_private)]
 
 pub use self::Piece::*;
 pub use self::Position::*;

src/libtest/lib.rs

@@ -25,7 +25,7 @@
 #![feature(asm)]
 #![cfg_attr(stage0, feature(cfg_target_vendor))]
 #![feature(fnbox)]
-#![cfg_attr(any(unix, target_os = "cloudabi"), feature(libc))]
+#![cfg_attr(any(unix, target_os = "cloudabi"), feature(libc, rustc_private))]
 #![feature(nll)]
 #![feature(set_stdio)]
 #![feature(panic_unwind)]