Mac OS X Mavericks(10.9.4)です。他のMacでは vagrant-omnibus プラグインをインストールできるのですが、

どうやら nokogiri のインストールで失敗している模様。

% vagrant plugin install vagrant-omnibus
Installing the 'vagrant-omnibus' plugin. This can take a few minutes...
Building nokogiri using packaged libraries.
Bundler, the underlying system Vagrant uses to install plugins,
reported an error. The error is shown below. These errors are usually
caused by misconfigured plugin installations or transient network
issues. The error from Bundler is:
An error occurred while installing nokogiri (, and Bundler cannot continue.
Make sure that `gem install nokogiri -v ''` succeeds before bundling.

ためしに nokogiri 単体で入るか Gemfile に書いてインストールしてみたらこんなエラーが・・・

Building nokogiri using packaged libraries.
Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension.
/Users/wnoguchi/.rbenv/versions/2.0.0-p481/bin/ruby extconf.rb
Building nokogiri using packaged libraries.