Use rustup rather than installing iOS stdlibs manually

Author: SSheldon

.travis.yml

@@ -10,8 +10,8 @@ env:
 matrix:
   include:
     - os: osx
-      osx_image: xcode7.2
-      rust: nightly
+      osx_image: xcode7.3
+      rust: stable
       env: IOS_ARCHS="i386 x86_64 armv7 armv7s aarch64"
 sudo: false
 install: ./travis_install.sh

travis_install.sh

@@ -2,15 +2,8 @@
 
 set -eu
 
-rust_ios_install() {
-    ios_stdlib="rust-std-nightly-${1}-apple-ios"
-    curl -O "https://static.rust-lang.org/dist/${ios_stdlib}.tar.gz"
-    tar xzf "${ios_stdlib}.tar.gz"
-    "./${ios_stdlib}/install.sh" --prefix=$(rustc --print sysroot)
-}
-
 for arch in $IOS_ARCHS; do
-    rust_ios_install "$arch"
+    rustup target add "${arch}-apple-ios"
 done
 
 if [ -n "$IOS_ARCHS" ]; then