http://tkymx83.hatenablog.com/entry/2017/04/03/231642
ここを参考にHome brewでclangをinstallしたいのですが

$ brew install clang

Error: No available formula with the name "clang"
==> Searching for a previously deleted formula...
Error: No previously deleted formula found.
==> Searching for similarly named formulae...
These similarly named formulae were found:
clang-format ✔                                       clang-format@3.8                                     emacs-clang-complete-async
To install one of them, run (for example):
brew install clang-format ✔
==> Searching taps...
Error: No formulae found in taps.

とエラーが出ます. どう対処したら良いでしょうか.