Unbreak travis by installing llvm-3.6

.travis.yml

@@ -13,10 +13,12 @@ env:
 before_install:
  - travis_retry sudo add-apt-repository -y ppa:hvr/ghc
  - travis_retry sudo add-apt-repository -y ppa:h-rayflood/gcc-upper
- - travis_retry sudo add-apt-repository -y ppa:h-rayflood/llvm-upper
+ - travis_retry sudo sh -c "echo 'deb http://llvm.org/apt/precise/ llvm-toolchain-precise-3.6-binaries main' >> /etc/apt/sources.list"
+ - wget -O - http://llvm.org/apt/llvm-snapshot.gpg.key | sudo apt-key add -
  - travis_retry sudo apt-get update
- - travis_retry sudo apt-get install cabal-install-1.18 ghc-7.6.3 alex-3.1.3 happy-1.19.4 llvm-3.5
- - export PATH=/opt/ghc/7.6.3/bin:/opt/cabal/1.18/bin:/opt/alex/3.1.3/bin:/opt/happy/1.19.4/bin:/usr/lib/llvm-3.5/bin:$PATH
+ - travis_retry sudo apt-get install cabal-install-1.18 ghc-7.6.3 alex-3.1.3 happy-1.19.4
+ - travis_retry sudo apt-get install llvm-3.6
+ - export PATH=/opt/ghc/7.6.3/bin:/opt/cabal/1.18/bin:/opt/alex/3.1.3/bin:/opt/happy/1.19.4/bin:/usr/lib/llvm-3.6/bin:$PATH
  - git config --global url."git://github.com/ghc/packages-".insteadOf     git://github.com/ghc/packages/
  - git config --global url."http://github.com/ghc/packages-".insteadOf    http://github.com/ghc/packages/
  - git config --global url."https://github.com/ghc/packages-".insteadOf   https://github.com/ghc/packages/