diff --git a/.travis.yml b/.travis.yml
index bb21f6e..8b3d470 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -275,10 +275,43 @@ matrix:
       env:
         - CXX_COMPILER=clang++ CC_COMPILER=clang CONFIGURATION=Debug
 
+    - os: osx
+      compiler: clang++
+      osx_image: xcode9.4
+      env:
+        - CXX_COMPILER=clang++ CC_COMPILER=clang CONFIGURATION=Debug
+
 install:
   - export CC=${CC_COMPILER}
   - export CXX=${CXX_COMPILER}
   - JOBS=2 # Travis machines have 2 cores.
+  - |
+    # If linux and clang install the right version of libc++.
+    if [[ "${TRAVIS_OS_NAME}" == "linux" && "${CXX%%+*}" == "clang" && -n "$(ls -A ${LLVM_INSTALL})" ]]; then
+      LLVM_INSTALL=${DEPS_DIR}/llvm/install
+      if   [[ "${CXX}" == "clang++-3.5" ]]; then LLVM_VERSION="3.6.2"; # libc++ bug uncaught_exception not yet implemented.
+      elif [[ "${CXX}" == "clang++-3.6" ]]; then LLVM_VERSION="3.6.2";
+      elif [[ "${CXX}" == "clang++-3.7" ]]; then LLVM_VERSION="3.7.1";
+      elif [[ "${CXX}" == "clang++-3.8" ]]; then LLVM_VERSION="3.8.1";
+      elif [[ "${CXX}" == "clang++-3.9" ]]; then LLVM_VERSION="3.9.1";
+      elif [[ "${CXX}" == "clang++-4.0" ]]; then LLVM_VERSION="4.0.1";
+      elif [[ "${CXX}" == "clang++-5.0" ]]; then LLVM_VERSION="5.0.2";
+      elif [[ "${CXX}" == "clang++-6.0" ]]; then LLVM_VERSION="6.0.1";
+      fi
+      LLVM_URL="http://llvm.org/releases/${LLVM_VERSION}/llvm-${LLVM_VERSION}.src.tar.xz"
+      LIBCXX_URL="http://llvm.org/releases/${LLVM_VERSION}/libcxx-${LLVM_VERSION}.src.tar.xz"
+      LIBCXXABI_URL="http://llvm.org/releases/${LLVM_VERSION}/libcxxabi-${LLVM_VERSION}.src.tar.xz"
+      mkdir -p llvm llvm/build llvm/projects/libcxx llvm/projects/libcxxabi
+      travis_retry wget -O - ${LLVM_URL} | tar --strip-components=1 -xJ -C llvm
+      travis_retry wget -O - ${LIBCXX_URL} | tar --strip-components=1 -xJ -C llvm/projects/libcxx
+      travis_retry wget -O - ${LIBCXXABI_URL} | tar --strip-components=1 -xJ -C llvm/projects/libcxxabi
+      (cd llvm/build && cmake .. -DCMAKE_INSTALL_PREFIX=${LLVM_INSTALL})
+      (cd llvm/build/projects/libcxx && sudo make install -j JOBS)
+      (cd llvm/build/projects/libcxxabi && sudo make install -j JOBS)
+      export CXXFLAGS="-isystem ${LLVM_INSTALL}/include/c++/v1"
+      export LDFLAGS="-L ${LLVM_INSTALL}/lib -l c++ -l c++abi"
+      export LD_LIBRARY_PATH="${LD_LIBRARY_PATH}:${LLVM_INSTALL}/lib"
+    fi
 
 before_script:
   - rm -rf build