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I am getting the following error while trying to install the gem dependencies:

An error occurred while installing nokogiri (1.5.9), and Bundler cannot
continue.
Make sure that `gem install nokogiri -v '1.5.9'` succeeds before bundling.

I did try to install this nokogiri package seperately and got the following output:

Building native extensions.  This could take a while...
ERROR:  Error installing nokogiri:
    ERROR: Failed to build gem native extension.

        /usr/local/bin/ruby extconf.rb
checking for libxml/parser.h... yes
checking for libxslt/xslt.h... no
-----
libxslt is missing.  please visit http://nokogiri.org/tutorials/installing_nokogiri.html for help with installing dependencies.
-----
*** 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-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

Gem files will remain installed in /usr/local/lib/ruby/gems/1.9.1/gems/nokogiri-1.5.9 for inspection.
Results logged to /usr/local/lib/ruby/gems/1.9.1/gems/nokogiri-1.5.9/ext/nokogiri/gem_make.out

Which in turns seems like doesn't working too. So, now what should I do please? Thanks.