tweak dependencies

Author: edwardvalentini

.travis.yml

@@ -25,7 +25,7 @@ matrix:
     - sudo apt-add-repository "deb http://apt.llvm.org/trusty/ llvm-toolchain-trusty-${LLVM_API_VERSION}
       main"
     - sudo apt-get update
-    - sudo apt-get install llvm-${LLVM_API_VERSION} llvm-${LLVM_API_VERSION}-runtime libc++1
+    - sudo apt-get install llvm-${LLVM_API_VERSION} llvm-${LLVM_API_VERSION}-runtime libllvm${LLVM_API_VERSION} libc++1  libstdc++6
     - sudo cp /usr/lib/x86_64-linux-gnu/libc++.so.1.0 /usr/lib/
     - sudo ln -sf /usr/lib/libc++.so.1.0 /usr/lib/libc++.so
     - sudo rm -rf /usr/local/clang-*/bin/llvm-config