message: Try with default gcc version
diff: @@ -23,10 +23,11 @@ addons:
  - ubuntu-toolchain-r-test
  #- llvm-toolchain-precise-3.9
  packages:
  - - g++-5 build-essential
  + - build-essential
  + #- g++-5
  #- clang-3.9
  #env: CC=clang-3.9 CXX=clang-3.9
  -env: CC=g++-5 CXX=g++-5
  +#env: CC=g++-5 CXX=g++-5
  # command to install dependencies
  