title: Problems installing Nokogiri (1.5.2) on Ubuntu 12.10
body: <p>I'm running Ubuntu 12.10, and, when I run the command:</p>
  
  <pre><code>bundle install
  </code></pre>
  
  <p>I get: </p>
  
  <pre><code>Installing nokogiri (1.5.2) with native extensions 
  Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension.
  
  /usr/bin/ruby1.9.1 extconf.rb 
  extconf.rb:10: Use RbConfig instead of obsolete and deprecated Config.
  checking for libxml/parser.h... yes
  checking for libxslt/xslt.h... yes
  checking for libexslt/exslt.h... yes
  checking for iconv_open() in iconv.h... yes
  checking for xmlParseDoc() in -lxml2... yes
  checking for xsltParseStylesheetDoc() in -lxslt... yes
  checking for exsltFuncRegister() in -lexslt... yes
  checking for xmlHasFeature()... yes
  checking for xmlFirstElementChild()... yes
  checking for xmlRelaxNGSetParserStructuredErrors()... yes
  checking for xmlRelaxNGSetParserStructuredErrors()... yes
  checking for xmlRelaxNGSetValidStructuredErrors()... yes
  checking for xmlSchemaSetValidStructuredErrors()... yes
  checking for xmlSchemaSetParserStructuredErrors()... yes
  creating Makefile
  
  make
  compiling xml_processing_instruction.c
  compiling xml_node.c
  compiling html_entity_lookup.c
  compiling xml_syntax_error.c
  compiling xml_document.c
  xml_document.c: In function ‘set_encoding’:
  xml_document.c:159:12: warning: cast discards ‘__attribute__((const))’ qualifier from pointer target type [-Wcast-qual]
  xml_document.c: In function ‘canonicalize’:
  xml_document.c:505:15: warning: cast discards ‘__attribute__((const))’ qualifier from pointer target type [-Wcast-qual]
  compiling xml_encoding_handler.c
  compiling xml_namespace.c
  xml_namespace.c: In function ‘prefix’:
  xml_namespace.c:14:13: warning: variable ‘doc’ set but not used [-Wunused-but-set-variable]
  xml_namespace.c: In function ‘href’:
  xml_namespace.c:33:13: warning: variable ‘doc’ set but not used [-Wunused-but-set-variable]
  compiling xml_entity_decl.c
  compiling xml_attribute_decl.c
  compiling xml_comment.c
  compiling xml_dtd.c
  compiling xml_xpath_context.c
  xml_xpath_context.c: In function ‘xpath_generic_exception_handler’:
  xml_xpath_context.c:189:3: error: format not a string literal and no format arguments [-Werror=format-security]
  cc1: some warnings being treated as errors
  make: *** [xml_xpath_context.o] Error 1
  
  
  Gem files will remain installed in /home/site/.bundler/tmp/19240/gems/nokogiri-1.5.2 for inspection.
  Results logged to /home/site/.bundler/tmp/19240/gems/nokogiri-1.5.2/ext/nokogiri/gem_make.out
  An error occured while installing nokogiri (1.5.2), and Bundler cannot continue.
  Make sure that `gem install nokogiri -v '1.5.2'` succeeds before bundling.
  </code></pre>
  
  <p>When I run:</p>
  
  <pre><code>gem install nokogiri -v '1.5.2'
  </code></pre>
  
  <p>I get:</p>
  
  <pre><code>site@ubuntu:~/Documents/shopqi$ gem install nokogiri -v '1.5.2'
  malloc_limit=60000000 (8000000)
  free_min=50000 (4096)
  Building native extensions.  This could take a while...
  Successfully installed nokogiri-1.5.2
  1 gem installed
  Installing ri documentation for nokogiri-1.5.2...
  Installing RDoc documentation for nokogiri-1.5.2...
  site@ubuntu:~/Documents/shopqi$
  </code></pre>
  
  <p>There's no error, but if I try <code>bundle install</code> again I get the error that Nokogiri is not installed. </p>
  
  <p>the content of gem_make.out after running sudo gem install nokogiri -v '1.5.2' is:</p>
  
  <pre><code>/usr/bin/ruby1.9.1 extconf.rb
  extconf.rb:10: Use RbConfig instead of obsolete and deprecated Config.
  checking for libxml/parser.h... yes
  checking for libxslt/xslt.h... yes
  checking for libexslt/exslt.h... yes
  checking for iconv_open() in iconv.h... yes
  checking for xmlParseDoc() in -lxml2... yes
  checking for xsltParseStylesheetDoc() in -lxslt... yes
  checking for exsltFuncRegister() in -lexslt... yes
  checking for xmlHasFeature()... yes
  checking for xmlFirstElementChild()... yes
  checking for xmlRelaxNGSetParserStructuredErrors()... yes
  checking for xmlRelaxNGSetParserStructuredErrors()... yes
  checking for xmlRelaxNGSetValidStructuredErrors()... yes
  checking for xmlSchemaSetValidStructuredErrors()... yes
  checking for xmlSchemaSetParserStructuredErrors()... yes
  creating Makefile
  
  make
  compiling xml_processing_instruction.c
  compiling xml_node.c
  compiling html_entity_lookup.c
  compiling xml_syntax_error.c
  compiling xml_document.c
  xml_document.c: In function ‘set_encoding’:
  xml_document.c:159:12: warning: cast discards ‘__attribute__((const))’ qualifier from pointer target type [-Wcast-qual]
  xml_document.c: In function ‘canonicalize’:
  xml_document.c:505:15: warning: cast discards ‘__attribute__((const))’ qualifier from pointer target type [-Wcast-qual]
  compiling xml_encoding_handler.c
  compiling xml_namespace.c
  xml_namespace.c: In function ‘prefix’:
  xml_namespace.c:14:13: warning: variable ‘doc’ set but not used [-Wunused-but-set-variable]
  xml_namespace.c: In function ‘href’:
  xml_namespace.c:33:13: warning: variable ‘doc’ set but not used [-Wunused-but-set-variable]
  compiling xml_entity_decl.c
  compiling xml_attribute_decl.c
  compiling xml_comment.c
  compiling xml_dtd.c
  compiling xml_xpath_context.c
  xml_xpath_context.c: In function ‘xpath_generic_exception_handler’:
  xml_xpath_context.c:189:3: error: format not a string literal and no format arguments [-Werror=format-security]
  cc1: some warnings being treated as errors
  make: *** [xml_xpath_context.o] Error 1
  </code></pre>
  
  <p>Any help please?</p>