title: Can't build gem -- native extension build fails -- can you see why?
body: <p>I can't figure out what is going wrong here -- any ideas??</p>
  
  <p>I'm running on a Ubuntu 8.04 LTS, and have installed libxml2 and libxslt from these instructions:</p>
  
  <p><code>http://www.techsww.com/tutorials/libraries/libxml/installation/installing_libxml_on_ubuntu_linux.php</code></p>
  
  <p><code>http://www.techsww.com/tutorials/libraries/libxslt/installation/installing_libxslt_on_ubuntu_linux.php</code></p>
  
  <p>However, I installed the latest versions:</p>
  
  <p>libxslt-1.1.24<br>
    libxml2-2.7.3</p>
  
  <p>The install was uneventful</p>
  
  <p>-------------------- I set <code>LD_LIBRARY_PATH</code> ----------------------------------</p>
  
  <p>echo <code>$LD_LIBRARY_PATH</code><br>
    /usr/local/libxslt/lib:</p>
  
  <p>-------------  seems like the function is present -- at least based on the output of strings ------------<br>
  /usr/local/libxslt/lib$ strings * | grep ParseStylesheetDoc<br>
  xsltParseStylesheetDoc<br>
  xsltParseStylesheetDoc<br>
  xsltParseStylesheetDoc<br>
  xsltParseStylesheetDoc<br>
  xsltParseStylesheetDoc<br>
  xsltParseStylesheetDoc<br>
  xsltParseStylesheetDoc  </p>
  
  <p>----------------------- But the compile still fails   ----------------------------------------</p>
  
  <p>sudo gem install webrat<br>
  Building native extensions.  This could take a while...<br>
  ERROR:  Error installing webrat:<br>
        ERROR: Failed to build gem native extension.  </p>
  
  <p>/usr/local/bin/ruby extconf.rb install webrat<br>
  checking for iconv.h in /opt/local/include/,/opt/local/include/libxml2,/opt/local/include,/opt/local/include,/opt/local/include/libxml2,/usr/local/include,/usr/local/include/libxml2,/usr/local/include,/usr/local/include/libxml2,/usr/include,/usr/include/libxml2... yes<br>
  checking for libxml/parser.h in /opt/local/include/,/opt/local/include/libxml2,/opt/local/include,/opt/local/include,/opt/local/include/libxml2,/usr/local/include,/usr/local/include/libxml2,/usr/local/include,/usr/local/include/libxml2,/usr/include,/usr/include/libxml2... yes<br>
  checking for libxslt/xslt.h in /opt/local/include/,/opt/local/include/libxml2,/opt/local/include,/opt/local/include,/opt/local/include/libxml2,/usr/local/include,/usr/local/include/libxml2,/usr/local/include,/usr/local/include/libxml2,/usr/include,/usr/include/libxml2... yes<br>
  checking for libexslt/exslt.h in /opt/local/include/,/opt/local/include/libxml2,/opt/local/include,/opt/local/include,/opt/local/include/libxml2,/usr/local/include,/usr/local/include/libxml2,/usr/local/include,/usr/local/include/libxml2,/usr/include,/usr/include/libxml2... yes<br>
  checking for xmlParseDoc() in -lxml2... yes<br>
  checking for xsltParseStylesheetDoc() in -lxslt... no<br>
  libxslt is missing.  try 'port install libxslt' or 'yum install libxslt-devel'<br>
  <code>*** extconf.rb failed ***</code><br>
  Could not create Makefile due to some reason, probably lack of<br>
  necessary libraries and/or headers.  Check the mkmf.log file for more<br>
  details.  You may need configuration options.  </p>
  
  <p><code>Provided configuration options:<br>
        --with-opt-dir<br>
        --without-opt-dir<br>
        --with-opt-include<br>
        --without-opt-include=${opt-dir}/include<br>
        --with-opt-lib<br>
        --without-opt-lib=${opt-dir}/lib<br>
        --with-make-prog<br>
        --without-make-prog<br>
        --srcdir=.<br>
        --curdir<br>
        --ruby=/usr/local/bin/ruby<br>
        --with-iconv-dir<br>
        --without-iconv-dir<br>
        --with-iconv-include<br>
        --without-iconv-include=${iconv-dir}/include<br>
        --with-iconv-lib<br>
        --without-iconv-lib=${iconv-dir}/lib<br>
        --with-xml2-dir<br>
        --without-xml2-dir<br>
        --with-xml2-include<br>
        --without-xml2-include=${xml2-dir}/include<br>
        --with-xml2-lib<br>
        --without-xml2-lib=${xml2-dir}/lib<br>
        --with-xslt-dir<br>
        --without-xslt-dir<br>
        --with-xslt-include<br>
        --without-xslt-include=${xslt-dir}/include<br>
        --with-xslt-lib<br>
        --without-xslt-lib=${xslt-dir}/lib<br>
        --with-xml2lib<br>
        --without-xml2lib<br>
        --with-xsltlib<br>
        --without-xsltlib</code>  </p>
  
  <p>Gem files will remain installed in /usr/local/lib/ruby/gems/1.8/gems/nokogiri-1.3.3 for inspection.<br>
  Results logged to /usr/local/lib/ruby/gems/1.8/gems/nokogiri-1.3.3/ext/nokogiri/gem_make.out</p>