Travis: fix for Linux clang builds

.travis.yml

@@ -7,6 +7,7 @@ notifications:
 cache:
   directories:
     - ci-scripts/local
+    - ci-scripts/clang
 
 matrix:
   include:
@@ -44,27 +45,24 @@ matrix:
         apt:
           sources:
             - ubuntu-toolchain-r-test
-            - llvm-toolchain-precise-3.6
           packages:
-            - clang-3.6
             - libgsl0-dev
             - flex
             - bison
-      env: VERSION=-3.6
+      env: CLANG_LINK=http://llvm.org/releases/3.6.0/clang+llvm-3.6.0-x86_64-linux-gnu-ubuntu-14.04.tar.xz
     - compiler: clang
       addons:
         apt:
           sources:
             - ubuntu-toolchain-r-test
-            - llvm-toolchain-precise-3.7
           packages:
-            - clang-3.7
             - libgsl0-dev
             - flex
             - bison
-      env: VERSION=-3.7
+      env: CLANG_LINK=http://llvm.org/releases/3.7.0/clang+llvm-3.7.0-x86_64-linux-gnu-ubuntu-14.04.tar.xz
 
 before_install:
+  - if [[ "$TRAVIS_OS_NAME" == "linux" ]] && [[ "$CC" == "clang" ]] && [ ! -e clang ]; then wget $CLANG_LINK; tar -xf `basename $CLANG_LINK`; mv clang* clang; cd clang; export PATH="`pwd`/bin:${PATH}"; cd -; fi
   - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then brew update; fi
   - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then brew install gsl; fi
   - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then brew install bison flex; export PATH="/usr/local/opt/flex/bin:/usr/local/opt/bison/bin:$PATH"; fi