As you can see below, libv8 installs fine, but therubyracer doesn\'t. I\'m using Mac 10.7.4.
~/.rvm/rubies/ruby-1.9.3-p125/lib/ruby/1.9.1> gem install lib
According to https://github.com/cowboyd/therubyracer/issues/420#issuecomment-253592865
gem uninstall therubyracer gem uninstall libv8 brew uninstall v8 brew install v8 gem install libv8 gem install therubyracer
It helped me. Parameters: ruby 2.3.3, rails 4.2.9
ruby 2.3.3
rails 4.2.9