ERROR: Error installing nokogiri:
ERROR: Failed to build gem native extension.
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby extconf.rb
mkmf.rb can't find header files for ruby at /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/ruby.h
Gem files will remain installed in /Library/Ruby/Gems/1.8/gems/nokogiri-1.5.5 for inspection.
Results logged to /Library/Ruby/Gems/1.8/gems/nokogiri-1.5.5/ext/nokogiri/gem_make.out
Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension./System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby extconf.rbchecking for libxml/parser.h... yeschecking for libxslt/xslt.h... yeschecking for libexslt/exslt.h... yeschecking for iconv_open() in iconv.h... nochecking for iconv_open() in -liconv... yeschecking for xmlParseDoc() in -lxml2... yeschecking for xsltParseStylesheetDoc() in -lxslt... yeschecking for exsltFuncRegister() in -lexslt... yeschecking for xmlHasFeature()... yeschecking for xmlFirstElementChild()... yeschecking for xmlRelaxNGSetParserStructuredErrors()... yeschecking for xmlRelaxNGSetParserStructuredErrors()... yeschecking for xmlRelaxNGSetValidStructuredErrors()... yeschecking for xmlSchemaSetValidStructuredErrors()... yeschecking for xmlSchemaSetParserStructuredErrors()... yescreating Makefilemake/usr/bin/gcc-4.2 -I. -I. -I/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/universal-darwin12.0 -I. -DHAVE_XMLHASFEATURE -DHAVE_XMLFIRSTELEMENTCHILD -DHAVE_XMLRELAXNGSETPARSERSTRUCTUREDERRORS -DHAVE_XMLRELAXNGSETPARSERSTRUCTUREDERRORS -DHAVE_XMLRELAXNGSETVALIDSTRUCTUREDERRORS -DHAVE_XMLSCHEMASETVALIDSTRUCTUREDERRORS -DHAVE_XMLSCHEMASETPARSERSTRUCTUREDERRORS -I-I-I/opt/local/include -I-I-I/usr/local/include -I-I-I/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/include -I-I-I/usr/include -I-I-I/usr/include/libxml2 -I/usr/local/Cellar/libxml2/2.8.0/include/libxml2 -I/opt/local/include/libxml2 -I/usr/local/include/libxml2 -I/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/include/libxml2 -I-I/opt/local/include -I-I/usr/local/include -I-I/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/include -I-I/usr/include -I-I/usr/include/libxml2 -I/opt/local/include -I/usr/local/include -I/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/include -I/usr/include -I/usr/include/libxml2 -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE -fno-common -g -Os -pipe -fno-common -DENABLE_DTRACE -fno-common -pipe -fno-common -g -DXP_UNIX -O3 -Wall -Wcast-qual -Wwrite-strings -Wconversion -Wmissing-noreturn -Winline -c html_document.cmake: /usr/bin/gcc-4.2: No such file or directorymake: *** [html_document.o] Error 1Gem files will remain installed in /Users/bradwrage/.bundler/tmp/19839/gems/nokogiri-1.5.5 for inspection.Results logged to /Users/bradwrage/.bundler/tmp/19839/gems/nokogiri-1.5.5/ext/nokogiri/gem_make.outAn error occurred while installing nokogiri (1.5.5), and Bundler cannot continue.Make sure that `gem install nokogiri -v '1.5.5'` succeeds before bundling.