Rubyonrails 安装mysql2(0.4.8)时出错，Bundler无法继续

如何在ruby on rail中修复此错误.

source 'https://rubygems.org'

git_source(:github) do |repo_name|
  repo_name = "#{repo_name}/#{repo_name}" unless repo_name.include?("/")
  "https://github.com/#{repo_name}.git"
end


# Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
gem 'rails', '~> 5.0.2'
# Use sqlite3 as the database for Active Record
gem 'sqlite3'
# Use Puma as the app server
gem 'puma', '~> 3.0'
# Use SCSS for stylesheets
gem 'sass-rails', '~> 5.0'
# Use Uglifier as compressor for JavaScript assets
gem 'uglifier', '>= 1.3.0'
# Use CoffeeScript for .coffee assets and views
gem 'coffee-rails', '~> 4.2'
# See https://github.com/rails/execjs#readme for more supported runtimes
# gem 'therubyracer', platforms: :ruby
gem 'mysql 2', '0.4.8'
# Use jquery as the JavaScript library
gem 'jquery-rails'
# Turbolinks makes navigating your web application faster. Read more: https://github.com/turbolinks/turbolinks
gem 'turbolinks', '~> 5'
# Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
gem 'jbuilder', '~> 2.5'
# Use Redis adapter to run Action Cable in production
# gem 'redis', '~> 3.0'
# Use ActiveModel has_secure_password
# gem 'bcrypt', '~> 3.1.7'

# Use Capistrano for deployment
# gem 'capistrano-rails', group: :development

group :development, :test do
  # Call 'byebug' anywhere in the code to stop execution and get a debugger console
  gem 'byebug', platform: :mri
end

group :development do
  # Access an IRB console on exception pages or by using <%= console %> anywhere in the code.
  gem 'web-console', '>= 3.3.0'
  gem 'listen', '~> 3.0.5'
  # Spring speeds up development by keeping your application running in the background. Read more: https://github.com/rails/spring
  gem 'spring'
  gem 'spring-watcher-listen', '~> 2.0.0'
end

# Windows does not include zoneinfo files, so bundle the tzinfo-data gem
gem 'tzinfo-data', platforms: [:mingw, :mswin, :x64_mingw, :jruby]

gem 'spree', '~> 3.2.1'
gem 'spree_auth_devise', github: 'spree/spree_auth_devise'
gem 'spree_gateway', github: 'spree/spree_gateway'
gem 'spree_i18n', github: 'spree-contrib/spree_i18n', branch: 'master'

我运行了"bundle安装"，出现了这个错误.

这个ruby on rails使用Spree框架.

编辑:

Gem::Ext::BuildError: ERROR: Failed to build gem native extension.

    current directory: /Users/admin/.rvm/gems/ruby-2.4.1/gems/mysql2-0.4.8/ext/mysql2
/Users/admin/.rvm/rubies/ruby-2.4.1/bin/ruby -r ./siteconf20170803-6579-foq4sg.rb extconf.rb
checking for rb_absint_size()... yes

我运行了"bundle install"，但由于此错误，无法成功执行此命令.