message: [CMake] Use CLANG_INCLUDE_DIRS
  Instead of listing all the clang include directories manually, just use
  CLANG_INCLUDE_DIRS from the Clang CMake package that we import.
diff: @@ -129,10 +129,8 @@ if (CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
  set(CMAKE_INCLUDE_CURRENT_DIR ON)
  include_directories("${LLVM_BINARY_DIR}/include"
  - "${LLVM_BINARY_DIR}/tools/clang/include"
  "${LLVM_MAIN_INCLUDE_DIR}"
  - "${PATH_TO_CLANG_BUILD}/include"
  - "${LLDB_PATH_TO_CLANG_SOURCE}/include"
  + "${CLANG_INCLUDE_DIRS}"
  "${LLDB_PATH_TO_SWIFT_BUILD}/include"
  "${LLDB_PATH_TO_SWIFT_SOURCE}/include"
  "${CMAKE_CURRENT_SOURCE_DIR}/source")
  