Try something

Author: CodaFi

.travis.yml

@@ -7,17 +7,21 @@ matrix:
       language: objective-c
       osx_image: xcode8
       before_install:
-        - cp ./cllvm.pc /usr/local/lib/pkgconfig/cllvm.pc 
+        - cp ./cllvm.pc /usr/local/lib/pkgconfig/cllvm.pc
         - brew install llvm
       script:
-        - swift build	
+        - swift build
     - os: linux
       language: generic
       sudo: required
       dist: trusty
       before_install:
         - export PKG_CONFIG_PATH=${PWD}:"${PKG_CONFIG_PATH}"
-        - sudo aptitude install llvm
+        - export PKG_CONFIG_PATH=/usr/include/llvm-c-3.9:"${PKG_CONFIG_PATH}"
+        - wget -O - http://apt.llvm.org/llvm-snapshot.gpg.key | sudo apt-key add -
+        - sudo apt-add-repository "deb http://apt.llvm.org/trusty/ llvm-toolchain-trusty-3.9 main"
+        - sudo apt-get update
+        - sudo apt-get install llvm-3.9
         - wget -q -O - https://swift.org/keys/all-keys.asc | gpg --import -
         - wget https://swift.org/builds/swift-3.0-release/ubuntu1404/swift-3.0-RELEASE/swift-3.0-RELEASE-ubuntu14.04.tar.gz
         - tar xzf swift-3.0-RELEASE-ubuntu14.04.tar.gz