title: Unable to install the gem therubyracer
body: <p>While running the bundle install command, I encountered the following error:</p>
  
  <blockquote>
    <p>Installing libv8 (3.3.10.4) with native extensions
    Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native
    extension .</p>
  
  <pre><code>    D:/RailsInstaller/Ruby1.9.2/bin/ruby.exe extconf.rb
  </code></pre>
    
    <p><strong>* extconf.rb failed *</strong> Could not create Makefile due to some reason, probably lack of necessary libraries and/or headers.  Check
    the mkmf.log file for more details.  You may need configuration
    options.</p>
    
    <p>Provided configuration options:
            --with-opt-dir
            --without-opt-dir
            --with-opt-include
            --without-opt-include=${opt-dir}/include
            --with-opt-lib
            --without-opt-lib=${opt-dir}/lib
            --with-make-prog
            --without-make-prog
            --srcdir=.
            --curdir
            --ruby=D:/RailsInstaller/Ruby1.9.2/bin/ruby Checking for Python...Unable to build libv8: Python not found!</p>
    
    <p>Gem files will remain installed in
    D:/RailsInstaller/Ruby1.9.2/lib/ruby/gems/1.9 .1/gems/libv8-3.3.10.4
    for inspection. Results logged to
    D:/RailsInstaller/Ruby1.9.2/lib/ruby/gems/1.9.1/gems/libv8-3.3
    .10.4/ext/libv8/gem_make.out An error occured while installing libv8
    (3.3.10.4), and Bundler cannot continue.</p>
    
    <p>Make sure that <code>gem install libv8 -v '3.3.10.4'</code> succeeds before
    bundling.</p>
  </blockquote>
  
  <p>Environment: Ruby 1.9.2 Rails 3.2.1 Gem : 1.8.17
  <strong>Gemfile</strong></p>
  
  <pre><code>source 'https://rubygems.org'
  
      gem 'rails', '3.2.1'
  
      gem 'sqlite3'
  
      gem "heroku"
  
      group :production do
        gem 'pg'
      end
  
      gem 'execjs'
      gem 'therubyracer'
      gem 'libv8', '3.3.10.4'
  
  
      group :assets do
        gem 'sass-rails',   '~&gt; 3.2.3'
        gem 'coffee-rails', '~&gt; 3.2.1'
        gem 'uglifier', '&gt;= 1.0.3'
      end
  
      gem 'jquery-rails'
  </code></pre>
  
  <p>Can anybody tell me why I am seeing this error, and how to fix it?</p>