message: Add build-essential
diff: @@ -23,7 +23,7 @@ addons:
  - ubuntu-toolchain-r-test
  #- llvm-toolchain-precise-3.9
  packages:
  - - g++-5
  + - g++-5 build-essential
  #- clang-3.9
  #env: CC=clang-3.9 CXX=clang-3.9
  env: CC=g++-5 CXX=g++-5
  