title: can't install libxml-ruby for rails 2.3.14
body: <p>I'm getting this error when executing 'bundle install':</p>
  
  <pre><code>..........
  
  Installing libxml-ruby (2.7.0) 
  Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension.
  
      /home/ubuntu/.rvm/rubies/ruby-1.8.7-p374/bin/ruby extconf.rb 
  checking for socket() in -lsocket... no
  checking for gethostbyname() in -lnsl... yes
  checking for atan() in -lm... no
  checking for atan() in -lm... yes
  checking for inflate() in -lz... yes
  checking for iconv_open() in -liconv... no
  checking for libiconv_open() in -liconv... no
  checking for libiconv_open() in -llibiconv... no
  checking for iconv_open() in -llibiconv... no
  checking for iconv_open() in -lc... yes
  checking for xmlParseDoc() in -lxml2... no
  checking for xmlParseDoc() in -llibxml2... no
  checking for xmlParseDoc() in -lxml2... no
  *** 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=/home/ubuntu/.rvm/rubies/ruby-1.8.7-p374/bin/ruby
      --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-zlib-dir
      --without-zlib-dir
      --with-zlib-include
      --without-zlib-include=${zlib-dir}/include
      --with-zlib-lib
      --without-zlib-lib=${zlib-dir}/lib
      --with-socketlib
      --without-socketlib
      --with-nsllib
      --without-nsllib
      --with-mlib
      --without-mlib
      --with-mlib
      --without-mlib
      --with-zlib
      --without-zlib
      --with-iconvlib
      --without-iconvlib
      --with-iconvlib
      --without-iconvlib
      --with-libiconvlib
      --without-libiconvlib
      --with-libiconvlib
      --without-libiconvlib
      --with-clib
      --without-clib
      --with-xml2-config
      --without-xml2-config
      --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-xml2lib
      --without-xml2lib
      --with-libxml2lib
      --without-libxml2lib
      --with-xml2lib
      --without-xml2lib
   extconf failure: need libxml2.
  
      Install the library or try one of the following options to extconf.rb:
  
        --with-xml2-config=/path/to/xml2-config
        --with-xml2-dir=/path/to/libxml2
        --with-xml2-lib=/path/to/libxml2/lib
        --with-xml2-include=/path/to/libxml2/include
  
  
  
  Gem files will remain installed in /home/ubuntu/.rvm/gems/ruby-1.8.7-p374@ieasy/gems/libxml-ruby-2.7.0 for inspection.
  Results logged to /home/ubuntu/.rvm/gems/ruby-1.8.7-p374@ieasy/gems/libxml-ruby-2.7.0/ext/libxml/gem_make.out
  
  An error occurred while installing libxml-ruby (2.7.0), and Bundler cannot continue.
  Make sure that `gem install libxml-ruby -v '2.7.0'` succeeds before bundling.
  </code></pre>
  
  <p>Not really sure what's wrong here.  This is working on my other box with the same ruby and rails version.  </p>
  
  <p>Been trying to figure this out but with no luck.</p>
  
  <p>Please help.  :( .. thanks!</p>