diff --git a/Cargo.lock b/Cargo.lock
index 77ebe5633f7..8a99d247fc8 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2992,6 +2992,7 @@ version = "0.0.1"
 dependencies = [
  "lazy_static 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "nonzero 0.0.1",
 ]
 
 [[package]]
diff --git a/components/constellation/Cargo.toml b/components/constellation/Cargo.toml
index 2d659bd4342..b9d6177273b 100644
--- a/components/constellation/Cargo.toml
+++ b/components/constellation/Cargo.toml
@@ -9,6 +9,9 @@ publish = false
 name = "constellation"
 path = "lib.rs"
 
+[features]
+unstable = ["servo_remutex/unstable"]
+
 [dependencies]
 backtrace = "0.3"
 bluetooth_traits = { path = "../bluetooth_traits" }
diff --git a/components/remutex/Cargo.toml b/components/remutex/Cargo.toml
index 8bb165d40df..b3937587a62 100644
--- a/components/remutex/Cargo.toml
+++ b/components/remutex/Cargo.toml
@@ -9,6 +9,10 @@ publish = false
 name = "servo_remutex"
 path = "lib.rs"
 
+[features]
+unstable = ["nonzero/unstable"]
+
 [dependencies]
 lazy_static = "0.2"
 log = "0.3.5"
+nonzero = {path = "../nonzero"}
diff --git a/components/remutex/lib.rs b/components/remutex/lib.rs
index 8f97da8351f..6793429bf1e 100644
--- a/components/remutex/lib.rs
+++ b/components/remutex/lib.rs
@@ -10,13 +10,13 @@
 //! It provides the same interface as https://github.com/rust-lang/rust/blob/master/src/libstd/sys/common/remutex.rs
 //! so if those types are ever exported, we should be able to replace this implemtation.
 
-#![feature(nonzero)]
+#![cfg_attr(feature = "unstable", feature(nonzero))]
 
-extern crate core;
+extern crate nonzero;
 #[macro_use] extern crate lazy_static;
 #[macro_use] extern crate log;
 
-use core::nonzero::NonZero;
+use nonzero::NonZeroUsize;
 use std::cell::{Cell, UnsafeCell};
 use std::ops::Deref;
 use std::sync::{LockResult, Mutex, MutexGuard, PoisonError, TryLockError, TryLockResult};
@@ -27,7 +27,7 @@ use std::sync::atomic::{AtomicUsize, Ordering};
 // TODO: can we use the thread-id crate for this?
 
 #[derive(Clone, Copy, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
-pub struct ThreadId(NonZero<usize>);
+pub struct ThreadId(NonZeroUsize);
 
 lazy_static!{ static ref THREAD_COUNT: AtomicUsize = AtomicUsize::new(1); }
 
@@ -35,7 +35,7 @@ impl ThreadId {
     #[allow(unsafe_code)]
     fn new() -> ThreadId {
         let number = THREAD_COUNT.fetch_add(1, Ordering::SeqCst);
-        ThreadId(NonZero::new(number).unwrap())
+        ThreadId(NonZeroUsize::new(number).unwrap())
     }
     pub fn current() -> ThreadId {
         THREAD_ID.with(|tls| tls.clone())
@@ -59,13 +59,13 @@ impl AtomicOptThreadId {
     #[allow(unsafe_code)]
     pub fn load(&self, ordering: Ordering) -> Option<ThreadId> {
         let number = self.0.load(ordering);
-        NonZero::new(number).map(ThreadId)
+        NonZeroUsize::new(number).map(ThreadId)
     }
     #[allow(unsafe_code)]
     pub fn swap(&self, value: Option<ThreadId>, ordering: Ordering) -> Option<ThreadId> {
         let number = value.map(|id| id.0.get()).unwrap_or(0);
         let number = self.0.swap(number, ordering);
-        NonZero::new(number).map(ThreadId)
+        NonZeroUsize::new(number).map(ThreadId)
     }
 }
 
diff --git a/components/servo/Cargo.toml b/components/servo/Cargo.toml
index ddfb938850b..55225482b46 100644
--- a/components/servo/Cargo.toml
+++ b/components/servo/Cargo.toml
@@ -22,7 +22,8 @@ unstable = [
     "euclid/unstable",
     "layout_thread/unstable",
     "msg/unstable",
-    "compositing/unstable"
+    "compositing/unstable",
+    "constellation/unstable",
 ]
 
 [dependencies]