brew doctor
    検査情報

    CFLAGS=-stdlib=libc++ pip install pycld2

    Looks like you’ve somehow managed to misconfigure both the Homebrew software and core Git repos.
    At this stage, it’s probably best to:

    1. Uninstall Homebrew: /bin/bash -c "$(curl -fsSL [https://raw.githubusercontent.com/Homebrew/install/master/uninstall.sh)"](https://raw.githubusercontent.com/Homebrew/install/master/uninstall.sh)%22)
    2. Go through the entire /usr/local directory hierarchy and manually clean up all the files/directories that the uninstall said it couldn’t clean up, as well as anything else that’s out of place, or that you don’t need any more.
    3. Reinstall Homebrew: /bin/bash -c "$(curl -fsSL [https://raw.githubusercontent.com/Homebrew/install/master/install.sh)"](https://raw.githubusercontent.com/Homebrew/install/master/install.sh)%22)
    4. Be especially careful with Git commands while in /usr/local/Homebrew and all the tap directories, unless you really know what you’re doing.

    Make a Time Machine backup first, in case you accidentally delete something you need later.

    参考：https://discourse.brew.sh/t/error-no-formulae-found-in-taps/8331/6