title: nokogiri gem installation error
body: <p>I know there are a lot of questions about this gem but no answer has worked for me.</p>
  
  <p>When I run in SSH <code>gem install nokogiri</code> I get this error:</p>
  
  <pre><code>Extracting libxml2-2.8.0.tar.gz into tmp/x86_64-unknown-linux-gnu/ports/libxml2/2.8.0... OK
  Running patch with /home/user58952277/.gem/ruby/1.9.3/gems/nokogiri-1.6.2.1/ports/patches/libxml2/0001-Fix-parser-local-buffers-size-problems.patch...
  Running 'patch' for libxml2 2.8.0... ERROR, review 'tmp/x86_64-unknown-linux-gnu/ports/libxml2/2.8.0/patch.log' to see what happened.
  *** 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.
  </code></pre>
  
  <p>My host told me that all libs are installed.
  Here are the full logs after executing the install nokogiri command:</p>
  
  <pre><code>Building native extensions.  This could take a while...
  Building nokogiri using packaged libraries.
  Building libxml2-2.8.0 for nokogiri with the following patches applied:
      - 0001-Fix-parser-local-buffers-size-problems.patch
      - 0002-Fix-entities-local-buffers-size-problems.patch
      - 0003-Fix-an-error-in-previous-commit.patch
      - 0004-Fix-potential-out-of-bound-access.patch
      - 0005-Detect-excessive-entities-expansion-upon-replacement.patch
      - 0006-Do-not-fetch-external-parsed-entities.patch
      - 0007-Enforce-XML_PARSER_EOF-state-handling-through-the-pa.patch
      - 0008-Improve-handling-of-xmlStopParser.patch
      - 0009-Fix-a-couple-of-return-without-value.patch
      - 0010-Keep-non-significant-blanks-node-in-HTML-parser.patch
      - 0011-Do-not-fetch-external-parameter-entities.patch
  ************************************************************************
  IMPORTANT!  Nokogiri builds and uses a packaged version of libxml2.
  
  If this is a concern for you and you want to use the system library
  instead, abort this installation process and reinstall nokogiri as
  follows:
  
      gem install nokogiri -- --use-system-libraries
  
  If you are using Bundler, tell it to use the option:
  
      bundle config build.nokogiri --use-system-libraries
      bundle install
  
  However, note that nokogiri does not necessarily support all versions
  of libxml2.
  
  For example, libxml2-2.9.0 and higher are currently known to be broken
  and thus unsupported by nokogiri, due to compatibility problems and
  XPath optimization bugs.
  ************************************************************************
  ERROR:  Error installing nokogiri:
      ERROR: Failed to build gem native extension.
  
          /opt/rubies/ruby-1.9.3/bin/ruby extconf.rb
  Building nokogiri using packaged libraries.
  checking for iconv.h... yes
  checking for iconv_open() in iconv.h... yes
  Building libxml2-2.8.0 for nokogiri with the following patches applied:
      - 0001-Fix-parser-local-buffers-size-problems.patch
      - 0002-Fix-entities-local-buffers-size-problems.patch
      - 0003-Fix-an-error-in-previous-commit.patch
      - 0004-Fix-potential-out-of-bound-access.patch
      - 0005-Detect-excessive-entities-expansion-upon-replacement.patch
      - 0006-Do-not-fetch-external-parsed-entities.patch
      - 0007-Enforce-XML_PARSER_EOF-state-handling-through-the-pa.patch
      - 0008-Improve-handling-of-xmlStopParser.patch
      - 0009-Fix-a-couple-of-return-without-value.patch
      - 0010-Keep-non-significant-blanks-node-in-HTML-parser.patch
      - 0011-Do-not-fetch-external-parameter-entities.patch
  ************************************************************************
  IMPORTANT!  Nokogiri builds and uses a packaged version of libxml2.
  
  If this is a concern for you and you want to use the system library
  instead, abort this installation process and reinstall nokogiri as
  follows:
  
      gem install nokogiri -- --use-system-libraries
  
  If you are using Bundler, tell it to use the option:
  
      bundle config build.nokogiri --use-system-libraries
      bundle install
  
  However, note that nokogiri does not necessarily support all versions
  of libxml2.
  
  For example, libxml2-2.9.0 and higher are currently known to be broken
  and thus unsupported by nokogiri, due to compatibility problems and
  XPath optimization bugs.
  ************************************************************************
  Extracting libxml2-2.8.0.tar.gz into tmp/x86_64-unknown-linux-gnu/ports/libxml2/2.8.0... OK
  Running patch with /home/user58952277/.gem/ruby/1.9.3/gems/nokogiri-1.6.2.1/ports/patches/libxml2/0001-Fix-parser-local-buffers-size-problems.patch...
  Running 'patch' for libxml2 2.8.0... ERROR, review 'tmp/x86_64-unknown-linux-gnu/ports/libxml2/2.8.0/patch.log' to see what happened.
  *** 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=/opt/rubies/ruby-1.9.3/bin/ruby
      --help
      --clean
      --use-system-libraries
      --enable-static
      --disable-static
      --with-zlib-dir
      --without-zlib-dir
      --with-zlib-include
      --without-zlib-include=${zlib-dir}/include
      --with-zlib-lib
      --without-zlib-lib=${zlib-dir}/lib
      --enable-cross-build
      --disable-cross-build
  /home/user58952277/.gem/ruby/1.9.3/gems/mini_portile-0.6.0/lib/mini_portile.rb:279:in `block in execute': Failed to complete patch task (RuntimeError)
      from /home/user58952277/.gem/ruby/1.9.3/gems/mini_portile-0.6.0/lib/mini_portile.rb:271:in `chdir'
      from /home/user58952277/.gem/ruby/1.9.3/gems/mini_portile-0.6.0/lib/mini_portile.rb:271:in `execute'
      from extconf.rb:282:in `block in patch'
      from extconf.rb:279:in `each'
      from extconf.rb:279:in `patch'
      from /home/user58952277/.gem/ruby/1.9.3/gems/mini_portile-0.6.0/lib/mini_portile.rb:108:in `cook'
      from extconf.rb:253:in `block in process_recipe'
      from extconf.rb:154:in `tap'
      from extconf.rb:154:in `process_recipe'
      from extconf.rb:419:in `&lt;main&gt;'
  </code></pre>