- Update Xcode command line tools (it should take a while)
$ xcode-select --install
- Update (Homebrew and) PhantomJS
$ brew update && brew upgrade phantomjs
- Update Ruby build
$ brew upgrade ruby-build
- Recompile Ruby
$ cat .ruby-version # 2.1.1
$ CC=gcc rbenv install 2.1.1 # confirm installation, it'll recompile Ruby
- Reset
rbenv
$ rbenv rehash && rbenv local 2.1.1