Run iOS on nightly instead of 1.41.0

Author: madsmtm

.travis.yml

@@ -56,17 +56,12 @@ jobs:
     os: linux
     rust: nightly
 
-  - name: iOS
+  - name: iOS nightly
     os: osx
     osx_image: xcode7.3
-    rust: 1.41.0
-    before_install: >
-      rustup target add
-      i386-apple-ios
-      x86_64-apple-ios
-      armv7-apple-ios
-      armv7s-apple-ios
-      aarch64-apple-ios
+    rust: nightly
+    before_install: rustup +nightly component add rust-src
     install: curl -LO https://github.com/SSheldon/rust-test-ios/releases/download/0.1.1/rust-test-ios && chmod +x rust-test-ios
+    before_script: echo "[unstable]\nbuild-std = []" > $HOME/.cargo/config.toml
     env: FEATURES="exception"
     script: ./rust-test-ios