diff --git a/Cargo.toml b/Cargo.toml
index e7b2b21..e466302 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -11,3 +11,6 @@ crunchy = "0.1.5"
 ethereum-types = { path ="../ethereum-types", features = ["std", "heapsizeof"] }
 quickcheck = "0.6"
 uint = { path = "../uint" }
+
+[features]
+use_asm = ["uint/use_asm", "ethereum-types/use_asm"]
\ No newline at end of file
diff --git a/build.rs b/build.rs
deleted file mode 100644
index 432acc3..0000000
--- a/build.rs
+++ /dev/null
@@ -1,17 +0,0 @@
-// Copyright 2015-2017 Parity Technologies
-//
-// 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.
-
-extern crate rustc_version;
-
-use rustc_version::{version_meta, Channel};
-
-fn main() {
-	if let Channel::Nightly = version_meta().unwrap().channel {
-		println!("cargo:rustc-cfg=asm_available");
-	}
-}
diff --git a/src/lib.rs b/src/lib.rs
index 342dbef..1ceb036 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,5 +1,3 @@
-#![cfg_attr(asm_available, feature(asm))]
-
 extern crate core;
 #[cfg(test)]
 #[macro_use]
@@ -13,4 +11,4 @@ extern crate crunchy;
 extern crate quickcheck;
 
 #[cfg(test)]
-pub mod uint_tests;
+pub mod uint_tests;
\ No newline at end of file