message: [travis-ci] disables boost
  Should be re-enabled by
diff: @@ -132,7 +132,7 @@ matrix:
  os: linux
  addons: *clang5
  - - env: CLANG_VERSION=5.0 BUILD_TYPE=Debug CPP=1z ASAN=Off LIBCXX=On HEADERS=On CLANG_MODULES=On BOOST=On
  + - env: CLANG_VERSION=5.0 BUILD_TYPE=Debug CPP=1z ASAN=Off LIBCXX=On HEADERS=On CLANG_MODULES=On BOOST=Off
  os: linux
  addons: *clang5
  