message: Added Xcode 9.4 and 10 to the travis build
  Added them to allow_failures. Let's see if it builds.
diff: @@ -37,6 +37,14 @@ matrix:
  env: C_COMPILER=clang CXX_COMPILER=clang++ GENERATOR_NAME="Xcode"
  osx_image: xcode9.3
  + - os: osx
  + env: C_COMPILER=clang CXX_COMPILER=clang++ GENERATOR_NAME="Xcode"
  + osx_image: xcode9.4
  +
  + - os: osx
  + env: C_COMPILER=clang CXX_COMPILER=clang++ GENERATOR_NAME="Xcode"
  + osx_image: xcode10
  +
  allow_failures:
  # These are additional combinations that we test but allow to fail, as they're either older compilers (g++-5) or
  # uncommon combinations that would need some workarounds or updates to work.
  @@ -47,6 +55,10 @@ matrix:
  osx_image: xcode9.2
  - env: C_COMPILER=clang CXX_COMPILER=clang++ GENERATOR_NAME="Xcode"
  osx_image: xcode9.3
  + - env: C_COMPILER=clang CXX_COMPILER=clang++ GENERATOR_NAME="Xcode"
  + osx_image: xcode9.4
  + - env: C_COMPILER=clang CXX_COMPILER=clang++ GENERATOR_NAME="Xcode"
  + osx_image: xcode10
  install:
  - |
  