message: ensure correct CXX_TYPE on travis
diff: @@ -7,6 +7,7 @@ before_script:
  - ${CXX} --version
  - echo "CXX=$CXX" > make/local
  - echo "CXXFLAGS+=$CXXFLAGS" >> make/local
  + - echo "CXX_TYPE=$CXX_TYPE" >> make/local
  linux_clang: &linux_clang
  os: linux
  @@ -50,20 +51,24 @@ matrix:
  env:
  - MATRIX_EVAL="CXX=clang++-3.8"
  CXXFLAGS="-stdlib=libc++"
  + CXX_TYPE="clang"
  PARALLEL=2
  - <<: *linux_gcc
  env:
  - MATRIX_EVAL="CXX=g++-4.9"
  + CXX_TYPE="gcc"
  PARALLEL=1
  - <<: *mpi_linux_clang
  env:
  - MATRIX_EVAL="CXX=\"mpicxx -cxx=clang++-3.8\""
  CXXFLAGS="-stdlib=libc++"
  + CXX_TYPE="clang"
  STAN_MPI=true
  PARALLEL=2
  - <<: *mpi_linux_gcc
  env:
  - MATRIX_EVAL="CXX=\"mpicxx -cxx=g++-4.9\""
  + CXX_TYPE="gcc"
  STAN_MPI=true
  PARALLEL=1
  