* progress on clang compilation

.travis.yml

@@ -8,7 +8,12 @@ before_install:
   - sudo add-apt-repository -y "deb http://archive.ubuntu.com/ubuntu/ trusty main universe"
   - sudo apt-get update -qq
   - sudo apt-get install root-system -y
-  - root-config --version
+  - if [ "$CXX" == "clang++" ]; then sudo add-apt-repository -y ppa:h-rayflood/llvm; fi 
+
+install:
+  # clang 3.4
+  - if [ "$CXX" == "clang++" ]; then sudo apt-get install --allow-unauthenticated -qq clang-3.4; fi
+  - if [ "$CXX" == "clang++" ]; then export CXX="clang++-3.4"; fi
 
 script:
   - cd NPLib