# uname -a Linux ip-10-122-6-110 3.2.30-49.59.amzn1.x86_64 #1 SMP Wed Oct 3 19:54:33 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux
# ruby -v ruby 1.8.7 (2012-10-12 patchlevel 371) [x86_64-linux]
# gem -v 1.8.11
# gem install json Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension. /usr/bin/ruby extconf.rb mkmf.rb can't find header files for ruby at /usr/lib/ruby/ruby.h Gem files will remain installed in /home/redmine/.bundler/tmp/5531/gems/json-1.7.7 for inspection. Results logged to /home/redmine/.bundler/tmp/5531/gems/json-1.7.7/ext/json/ext/generator/gem_make.out An error occurred while installing json (1.7.7), and Bundler cannot continue. Make sure that `gem install json -v '1.7.7'` succeeds before bundling.
ruby-develが必要。さらに、gcc、makeなどの開発環境も必要なので、yum でインストールする。
yum install ruby-devel gcc makeTweet