message: Update scripts/Xcode/build-llvm.py to use llvm/clang 4 branch
diff: @@ -22,12 +22,12 @@ def LLVM_HASH_INCLUDES_DIFFS():
  def LLVM_REF():
  - llvm_ref = "master"
  + llvm_ref = "release_40"
  return llvm_ref
  def CLANG_REF():
  - clang_ref = "master"
  + clang_ref = "release_40"
  return clang_ref
  # For use with Xcode-style builds
  