Я работаю над приложением rails, которое позволяет прикреплять изображения к каждой учетной записи. Я использую скрепки и веб-сервисы Amazon:

gem 'paperclip'
gem 'aws-sdk'

Когда я запускаю пакетную установку, я получаю это сообщение:

Сбой extconf, код выхода 1

Gem files will remain installed in /usr/local/rvm/gems/ruby-2.1.2/gems/nokogiri-1.6.5 for inspection.
Results logged to /usr/local/rvm/gems/ruby-2.1.2/extensions/x86_64-darwin-13/2.1.0-static/nokogiri-1.6.5/gem_make.out
An error occurred while installing nokogiri (1.6.5), and Bundler cannot continue.
Make sure that `gem install nokogiri -v '1.6.5'` succeeds before bundling.

Когда я пытаюсь запустить 'gem install nokogiri', я получаю следующее сообщение:

Сбой extconf, код выхода 1

Gem files will remain installed in /usr/local/rvm/gems/ruby-2.1.2/gems/nokogiri-1.6.5 for inspection.
Results logged to /usr/local/rvm/gems/ruby-2.1.2/extensions/x86_64-darwin-13/2.1.0-static/nokogiri-1.6.5/gem_make.out

Моя ОС Mac OS X 10.9.4 Mavericks.Что тут происходит? Как я могу заставить nokogiri установить и вести себя правильно?

Трассировка полного стека:

Building native extensions with: '--use-system-libraries'
This could take a while...
ERROR:  Error installing nokogiri:
    ERROR: Failed to build gem native extension.

    /usr/local/rvm/rubies/ruby-2.1.2/bin/ruby extconf.rb --use-system-libraries
checking if the C compiler accepts ... yes
checking if the C compiler accepts -Wno-error=unused-command-line-argument-hard-error-in-future... yes
Building nokogiri using system libraries.
libxml2 version 2.6.21 or later is required!
*** 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/rvm/rubies/ruby-2.1.2/bin/ruby
    --help
    --clean
    --use-system-libraries
    --with-zlib-dir
    --without-zlib-dir
    --with-zlib-include
    --without-zlib-include=${zlib-dir}/include
    --with-zlib-lib
    --without-zlib-lib=${zlib-dir}/lib
    --with-xml2-dir
    --without-xml2-dir
    --with-xml2-include
    --without-xml2-include=${xml2-dir}/include
    --with-xml2-lib
    --without-xml2-lib=${xml2-dir}/lib
    --with-libxml-2.0-config
    --without-libxml-2.0-config
    --with-pkg-config
    --without-pkg-config
    --with-xslt-dir
    --without-xslt-dir
    --with-xslt-include
    --without-xslt-include=${xslt-dir}/include
    --with-xslt-lib
    --without-xslt-lib=${xslt-dir}/lib
    --with-libxslt-config
    --without-libxslt-config
    --with-exslt-dir
    --without-exslt-dir
    --with-exslt-include
    --without-exslt-include=${exslt-dir}/include
    --with-exslt-lib
    --without-exslt-lib=${exslt-dir}/lib
    --with-libexslt-config
    --without-libexslt-config

extconf failed, exit code 1

Gem files will remain installed in /usr/local/rvm/gems/ruby-2.1.2/gems/nokogiri-1.6.5 for inspection.
Results logged to /usr/local/rvm/gems/ruby-2.1.2/extensions/x86_64-darwin-13/2.1.0-static/nokogiri-1.6.5/gem_make.out