Use LLVM 3.7 to build

Author: TomBebbington

.travis.yml

@@ -1,5 +1,6 @@
 language: rust
 rust: beta
+sudo: required
 after_success: |
   [ $TRAVIS_BRANCH = master ] &&
   [ $TRAVIS_PULL_REQUEST = false ] &&
@@ -10,11 +11,11 @@ after_success: |
   git push -fq https://${GH_TOKEN}@github.com/${TRAVIS_REPO_SLUG}.git gh-pages
 before_install:
   - sudo sh -c "add-apt-repository -y ppa:ubuntu-toolchain-r/test"
-  - sudo sh -c "echo 'deb http://llvm.org/apt/precise/ llvm-toolchain-precise-3.6 main' >> /etc/apt/sources.list"
+  - sudo sh -c "echo 'deb http://llvm.org/apt/precise/ llvm-toolchain-precise-3.7 main' >> /etc/apt/sources.list"
   - wget -O - http://llvm.org/apt/llvm-snapshot.gpg.key | sudo apt-key add -
 install:
   - sudo apt-get update -qq
-  - sudo apt-get install -qq llvm-3.6 libllvm3.6 libllvm3.6-dbg cmake libedit-dev
+  - sudo apt-get install -qq llvm-3.7 libllvm3.7 libllvm3.7-dbg cmake libedit-dev
   - sudo ln -s /usr/bin/llvm-config-* /usr/bin/llvm-config
 script:
   - cargo build --verbose