Instalando a libv8 mais antiga no Yosemite

brew update
brew uninstall v8

brew install apple
-gcc42

ln
-s /usr/local/Cellar/apple-gcc42/4.2.1-5666.3/bin/gcc-4.2 /usr/local/bin/gcc

ln
-s /usr/local/Cellar/apple-gcc42/4.2.1-5666.3/bin/g++-4.2 /usr/local/bin/g++

ln
-s /usr/local/Cellar/apple-gcc42/4.2.1-5666.3/bin/cpp-4.2 /usr/local/bin/cpp

gem install libv8


gem install therubyracer


brew uninstall apple
-gcc42
rm
/usr/local/bin/gcc
rm
/usr/local/bin/g++
rm
/usr/local/bin/cpp