我如何在Heroku上使用rdiscount？(How can I use rdiscount on Heroku?)

我正在尝试将一个小测试应用推送到Heroku。这是App和Gem文件：

应用程序：

require 'sinatra' require 'haml' require 'rdiscount' set :markdown, :layout_engine => :haml, :layout => :layout get '/' do haml :index end get '/blog' do markdown :test end

的Gemfile：

source :rubygems gem 'sinatra' gem 'thin' gem 'haml' gem 'rdiscount'

在推送到Heroku之前，我运行bundle install 。但试图安装rdiscount gem时推向Heroku失败：

-----> Ruby/Rack app detected -----> Installing dependencies using Bundler version 1.3.0.pre.5 Running: bundle install --without development:test --path vendor/bundle --binstubs vendor/bundle/bin --deployment Fetching gem metadata from http://rubygems.org/.......... Fetching gem metadata from http://rubygems.org/.. Using daemons (1.1.9) Using eventmachine (1.0.0) Using haml (3.1.7) Using rack (1.4.3) Using rack-protection (1.3.2) installing rdiscount (2.0.7) Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension. /usr/local/bin/ruby extconf.rb checking for random()... yes checking for srandom()... yes checking for rand()... yes checking for srand()... yes checking size of unsigned long... long checking size of unsigned int... int no int with size 4 *** 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. 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=/usr/local/bin/ruby --with-rdiscount-dir --without-rdiscount-dir --with-rdiscount-include --without-rdiscount-include=${rdiscount-dir}/include --with-rdiscount-lib --without-rdiscount-lib=${rdiscount-dir}/lib Gem files will remain installed in /tmp/build_3aijv3ga0dy1y/vendor/bundle/ruby/1.9.1/gems/rdiscount-2.0.7 for inspection. Results logged to /tmp/build_3aijv3ga0dy1y/vendor/bundle/ruby/1.9.1/gems/rdiscount-2.0.7/ext/gem_make.out An error occurred while installing rdiscount (2.0.7), and Bundler cannot continue. Make sure that `gem install rdiscount -v '2.0.7'` succeeds before bundling. ! ! Failed to install gems via Bundler. ! ! Heroku push rejected, failed to compile Ruby/rack app

我明白rdiscount可能取决于其他一些Gem或库，并且这种依赖似乎没有解决。但是，我不明白如何解决这个问题。你能给我一些关于如何使这个工作的建议吗？

I am trying to push a small test app to Heroku. Here is the App and the Gem file:

App:

require 'sinatra' require 'haml' require 'rdiscount' set :markdown, :layout_engine => :haml, :layout => :layout get '/' do haml :index end get '/blog' do markdown :test end

Gemfile:

source :rubygems gem 'sinatra' gem 'thin' gem 'haml' gem 'rdiscount'

Before pushing to Heroku I run bundle install. But pushing to Heroku fails when trying to install the rdiscount gem:

-----> Ruby/Rack app detected -----> Installing dependencies using Bundler version 1.3.0.pre.5 Running: bundle install --without development:test --path vendor/bundle --binstubs vendor/bundle/bin --deployment Fetching gem metadata from http://rubygems.org/.......... Fetching gem metadata from http://rubygems.org/.. Using daemons (1.1.9) Using eventmachine (1.0.0) Using haml (3.1.7) Using rack (1.4.3) Using rack-protection (1.3.2) installing rdiscount (2.0.7) Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension. /usr/local/bin/ruby extconf.rb checking for random()... yes checking for srandom()... yes checking for rand()... yes checking for srand()... yes checking size of unsigned long... long checking size of unsigned int... int no int with size 4 *** 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. 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=/usr/local/bin/ruby --with-rdiscount-dir --without-rdiscount-dir --with-rdiscount-include --without-rdiscount-include=${rdiscount-dir}/include --with-rdiscount-lib --without-rdiscount-lib=${rdiscount-dir}/lib Gem files will remain installed in /tmp/build_3aijv3ga0dy1y/vendor/bundle/ruby/1.9.1/gems/rdiscount-2.0.7 for inspection. Results logged to /tmp/build_3aijv3ga0dy1y/vendor/bundle/ruby/1.9.1/gems/rdiscount-2.0.7/ext/gem_make.out An error occurred while installing rdiscount (2.0.7), and Bundler cannot continue. Make sure that `gem install rdiscount -v '2.0.7'` succeeds before bundling. ! ! Failed to install gems via Bundler. ! ! Heroku push rejected, failed to compile Ruby/rack app

I do understand that rdiscount might depend on some other Gems or libraries and this dependency does not seem to be resolved. However, I do not understand how to solve this problem. Could you give me some advice on how to get this to work?