Error Message “Xcode alone is not sufficient on Sierra”

Question

I\'d like to install openCV to vectorize image, but there\'s a series error message regarding Xcode and Ruby.

First, I use terminal to install openCV, brew install

Answer 1

I had the same problem. I installed 'Command Line Tools for XCode' (choose appropriate version) from https://developer.apple.com/download/more/ and restarted my terminal. Issue resolved :)