diff --git a/src/cgmath.rs b/src/cgmath.rs
index b1dfea7..f7cc6eb 100644
--- a/src/cgmath.rs
+++ b/src/cgmath.rs
@@ -15,7 +15,7 @@
 
 #![crate_type = "rlib"]
 #![crate_type = "dylib"]
-#![feature(old_impl_check, plugin, core, std_misc)]
+#![feature(old_impl_check, plugin, core, std_misc, custom_derive)]
 #![plugin(rand_macros)]
 
 //! Computer graphics-centric math.