我尝试打开rails控制台，但发现如下错误：

rails c
Could not find nokogiri-1.6.0 in any of the sources
Run `bundle install` to install missing gems.

然后运行bundle install

Installing nokogiri (1.6.0)
Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension.

        /Users/liuxingqi/.rbenv/versions/1.9.3-p0/bin/ruby extconf.rb
Extracting libxml2-2.8.0.tar.gz into tmp/i686-apple-darwin11/ports/libxml2/2.8.0... OK
Running 'configure' for libxml2 2.8.0... OK
Running 'compile' for libxml2 2.8.0... OK
Running 'install' for libxml2 2.8.0... OK
Activating libxml2 2.8.0 (from /Users/liuxingqi/.rbenv/versions/1.9.3-p0/lib/ruby/gems/1.9.1/gems/nokogiri-1.6.0/ports/i686-apple-darwin11/libxml2/2.8.0)...
Extracting libxslt-1.1.26.tar.gz into tmp/i686-apple-darwin11/ports/libxslt/1.1.26... OK
Running 'configure' for libxslt 1.1.26... OK
Running 'compile' for libxslt 1.1.26... OK
Running 'install' for libxslt 1.1.26... OK
Activating libxslt 1.1.26 (from /Users/liuxingqi/.rbenv/versions/1.9.3-p0/lib/ruby/gems/1.9.1/gems/nokogiri-1.6.0/ports/i686-apple-darwin11/libxslt/1.1.26)...
checking for libxml/parser.h... *** 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=/Users/liuxingqi/.rbenv/versions/1.9.3-p0/bin/ruby
    --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-iconv-dir
    --without-iconv-dir
    --with-iconv-include
    --without-iconv-include=${iconv-dir}/include
    --with-iconv-lib
    --without-iconv-lib=${iconv-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-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-pkg-config
    --without-pkg-config
    --with-libxml-2.0-config
    --without-libxml-2.0-config
    --with-libiconv-config
    --without-libiconv-config
/Users/liuxingqi/.rbenv/versions/1.9.3-p0/lib/ruby/1.9.1/mkmf.rb:381:in `try_do': The compiler failed to generate an executable file. (RuntimeError)
You have to install development tools first.
    from /Users/liuxingqi/.rbenv/versions/1.9.3-p0/lib/ruby/1.9.1/mkmf.rb:506:in `try_cpp'
    from /Users/liuxingqi/.rbenv/versions/1.9.3-p0/lib/ruby/1.9.1/mkmf.rb:970:in `block in find_header'
    from /Users/liuxingqi/.rbenv/versions/1.9.3-p0/lib/ruby/1.9.1/mkmf.rb:790:in `block in checking_for'
    from /Users/liuxingqi/.rbenv/versions/1.9.3-p0/lib/ruby/1.9.1/mkmf.rb:284:in `block (2 levels) in postpone'
    from /Users/liuxingqi/.rbenv/versions/1.9.3-p0/lib/ruby/1.9.1/mkmf.rb:254:in `open'
    from /Users/liuxingqi/.rbenv/versions/1.9.3-p0/lib/ruby/1.9.1/mkmf.rb:284:in `block in postpone'
    from /Users/liuxingqi/.rbenv/versions/1.9.3-p0/lib/ruby/1.9.1/mkmf.rb:254:in `open'
    from /Users/liuxingqi/.rbenv/versions/1.9.3-p0/lib/ruby/1.9.1/mkmf.rb:280:in `postpone'
    from /Users/liuxingqi/.rbenv/versions/1.9.3-p0/lib/ruby/1.9.1/mkmf.rb:789:in `checking_for'
    from /Users/liuxingqi/.rbenv/versions/1.9.3-p0/lib/ruby/1.9.1/mkmf.rb:969:in `find_header'
    from extconf.rb:166:in `<main>'

Gem files will remain installed in /Users/liuxingqi/.rbenv/versions/1.9.3-p0/lib/ruby/gems/1.9.1/gems/nokogiri-1.6.0 for inspection.
Results logged to /Users/liuxingqi/.rbenv/versions/1.9.3-p0/lib/ruby/gems/1.9.1/gems/nokogiri-1.6.0/ext/nokogiri/gem_make.out

An error occurred while installing nokogiri (1.6.0), and Bundler cannot continue.
Make sure that `gem install nokogiri -v '1.6.0'` succeeds before bundling.

我的ruby版本：

ruby -v
ruby 1.9.3p0 (2011-10-30 revision 33570) [x86_64-darwin14.0.0]

操作系统：

OSX Yosemite 10.10.1

希望有人能帮助我！谢谢。