Install therubyracer gem on OSX 10.11 El Capitan

Question

bundle install fails with Make sure that `gem install therubyracer -v '0.12.1'` succeeds before bundling

gem install therubyracer -v '0.12.1' fails with errors which appear to relate to compilation

Prior to this, libv8 gem was having problems but that is now installed thanks to following SO posts.

Guides for fixing rubyracer for Mavericks seem to not work, due to changes in El Capitan?

ln: /usr/bin/cpp: Operation not permitted  

Answer 1

1. Install xcode through app store
2. Install 'command line tools' for xcode (xcode-select --install)
3. If using rbenv, after installing ruby you needed rbenv rehash

4. Assuming you have run gem install bundler and got errors, remove your mess:

   gem uninstall libv8 gem uninstall therubyracer brew rm v8 

5. Install gcc4.2

   brew tap homebrew/dupes brew install apple-gcc42 

6. Install v8

   brew tap homebrew/versions brew install v8-315 brew link --force v8-315 

7. Install gems

   gem install libv8 -- --with-system-v8 gem install therubyracer 

   if you get dyld: lazy symbol binding failed: Symbol not found, @rpbaltazar suggests an alternative:

   bundle config --local build.libv8 --with-cxx=/usr/local/bin/g++-4.2 bundle install 

Answer 2

I still had issues with @xxjjnn's answer. The following answer from github resolved it. My current setup: El Capitan 10.11.4 and Xcode 7.3.

brew tap homebrew/versions brew install v8-315  gem install libv8 -v '3.16.14.13' -- --with-system-v8 gem install therubyracer -- --with-v8-dir=/usr/local/opt/v8-315  bundle install