message: build: normalise paths before use
  Ensure that we normalise the paths to the CMake sytle paths before use.  If we
  do not do this, we will fail to configure on Windows.
diff: @@ -5,6 +5,14 @@ if (CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
  option(LLVM_INSTALL_TOOLCHAIN_ONLY "Only include toolchain files in the 'install' target." OFF)
  + file(TO_CMAKE_PATH "${LLDB_PATH_TO_LLVM_BUILD}" LLDB_PATH_TO_LLVM_BUILD)
  + file(TO_CMAKE_PATH "${LLDB_PATH_TO_CLANG_BUILD}" LLDB_PATH_TO_CLANG_BUILD)
  + file(TO_CMAKE_PATH "${LLDB_PATH_TO_CMARK_BUILD}" LLDB_PATH_TO_CMARK_BUILD)
  + file(TO_CMAKE_PATH "${LLDB_PATH_TO_SWIFT_BUILD}" LLDB_PATH_TO_SWIFT_BUILD)
  +
  + file(TO_CMAKE_PATH "${LLDB_PATH_TO_CLANG_SOURCE}" LLDB_PATH_TO_CLANG_SOURCE)
  + file(TO_CMAKE_PATH "${LLDB_PATH_TO_SWIFT_SOURCE}" LLDB_PATH_TO_SWIFT_SOURCE)
  +
  # Rely on llvm-config.
  set(CONFIG_OUTPUT)
  set(FIND_PATHS "")
  