libv8 and therubyracer installation problems on Mac OS 10.7.5

The error message is : Make sure that `gem install libv8 -v '3.16.14.7'` succeeds before bundling.

Solution: gem install libv8 -v '3.16.14.7' -- --with-system-v8

Make sure that `gem install therubyracer -v '0.12.1'` succeeds before bundling.

Solution : Change the Gemfile to specify the libv8 version:

gem 'libv8', '3.11.8.13' 

and run bundle