title: bundle install: Failed to build gem native extension
body: <p>i have git clone git://github.com/jalagrange/excel_test_app.git
  I got the below error while the bundle install, This does not happen with other my applications.</p>
  
  <p>following error</p>
  
  <pre><code>Installing mysql2 (0.3.6) with native extensions
  Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension.
  
  C:/RailsInstaller/Ruby1.9.3/bin/ruby.exe extconf.rb
  checking for rb_thread_blocking_region()... yes
  checking for main() in -llibmysql... no
  *** extconf.rb failed ***
  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.
  </code></pre>
  
  <p>gemfile</p>
  
  <pre><code>    source 'http://rubygems.org'
  
  gem 'rails', '3.1.0'
  
  # Bundle edge Rails instead:
  # gem 'rails',     :git =&gt; 'git://github.com/rails/rails.git'
  
  gem 'sqlite3'
  gem "spreadsheet"
  gem "carrierwave"
  gem "mini_magick"
  gem 'flash_cookie_session'
  gem "pry"
  gem "haml"
  gem 'fog'
  
  # To use Delayed_job
  gem 'daemons'
  gem 'delayed_job_active_record'
  
  # Gems used only for assets and not required
  # in production environments by default.
  group :assets do
    gem 'sass-rails', "  ~&gt; 3.1.0"
    gem 'coffee-rails', "~&gt; 3.1.0"
    gem 'uglifier'
  end
  
  gem 'jquery-rails'
  
  # Use unicorn as the web server
  # gem 'unicorn'
  
  # Deploy with Capistrano
  # gem 'capistrano'
  
  # To use debugger
  # gem 'ruby-debug19', :require =&gt; 'ruby-debug'
  
  group :test do
    # Pretty printed test output
    gem 'turn', :require =&gt; false
  end
  
  
  group :development, :test do
    gem "mysql2", "0.3.6"
    gem "letter_opener"
    gem "pry"
  end
  </code></pre>
  
  <p>this question and answer not working for my problem..
  <a href="https://stackoverflow.com/questions/4304438/mysql-failed-to-build-gem-native-extension">gem install: Failed to build gem native extension (can&#39;t find header files)</a></p>
  
  <p>problem solved,
  i have run bundle update..
  thx all..</p>