deny warnings only on nightly

lints have changed between nightly and stable

Author: japaric

ci/script.sh

@@ -1,6 +1,10 @@
 set -euxo pipefail
 
 main() {
+    if [ $TRAVIS_RUST_VERSION = nightly ]; then
+        export RUSTFLAGS="-D warnings"
+    fi
+
     cargo check --target $TARGET
 
     if [ $TRAVIS_RUST_VERSION = nightly ]; then

src/lib.rs

@@ -32,7 +32,6 @@
 
 #![cfg_attr(feature = "inline-asm", feature(asm))]
 #![deny(missing_docs)]
-#![deny(warnings)]
 #![no_std]
 
 extern crate aligned;