Homebrew で「error: The following untracked working tree files would be overwritten by merge: Library/Formula/libarchive.rb」というエラーが発生した場合の対応MacOSXhomebrew $ brew update error: The following untracked working tree files would be overwritten by merge: Library/Formula/libarchive.rb Please move or remove them before you can merge. Aborting Error: Failure while executing: git pull -q origin refs/heads/ma