title: Trouble installing nokogiri with RVM 1.9.3 on Centos 6.2
body: <pre><code>/usr/local/rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:381:in `try_do': 
  The compiler failed to generate an executable file. (RuntimeError)
  You have to install development tools first.
  </code></pre>
  
  <p>I have installed ruby 1.9.3 using RVM on my CentOS 6.2 server. When I try to run <code>gem install nokogiri</code> it produces the the output below. I have already visited the nokogiri website and installed the libxml2 and libxslt dependencies using yum: </p>
  
  <pre><code>sudo yum install -y gcc ruby-devel libxml2 libxml2-devel libxslt libxslt-devel
  </code></pre>
  
  <p>I have also installed the libxml2 and libxslt packages using <code>rvm pkg install</code> and reinstalled ruby afterward. </p>
  
  <p>I have been searching for a solution, but I haven't found anything yet. Any ideas would be appreciated :)</p>
  
  <pre><code>Building native extensions.  This could take a while...
  ERROR:  Error installing nokogiri:
          ERROR: Failed to build gem native extension.
  
          /usr/local/rvm/rubies/ruby-1.9.3-p194/bin/ruby extconf.rb
  checking for libxml/parser.h... *** 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
          --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=/usr/local/rvm/rubies/ruby-1.9.3-p194/bin/ruby
          --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-iconv-dir
          --without-iconv-dir
          --with-iconv-include
          --without-iconv-include=${iconv-dir}/include
          --with-iconv-lib
          --without-iconv-lib=${iconv-dir}/lib
          --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-xslt-dir
          --without-xslt-dir
          --with-xslt-include
          --without-xslt-include=${xslt-dir}/include
          --with-xslt-lib
          --without-xslt-lib=${xslt-dir}/lib
          --with-libxslt-config
          --without-libxslt-config
          --with-pkg-config
          --without-pkg-config
          --with-libxml-2.0-config
          --without-libxml-2.0-config
          --with-libiconv-config
          --without-libiconv-config
  /usr/local/rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:381:in `try_do': The compiler failed to generate an executable file. (RuntimeError)
  You have to install development tools first.
          from /usr/local/rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:506:in `try_cpp'
          from /usr/local/rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:970:in `block in find_header'
          from /usr/local/rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:790:in `block in checking_for'
          from /usr/local/rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:284:in `block (2 levels) in postpone'
          from /usr/local/rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:254:in `open'
          from /usr/local/rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:284:in `block in postpone'
          from /usr/local/rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:254:in `open'
          from /usr/local/rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:280:in `postpone'
          from /usr/local/rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:789:in `checking_for'
          from /usr/local/rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:969:in `find_header'
          from extconf.rb:114:in `&lt;main&gt;'
  
  
  Gem files will remain installed in /usr/local/rvm/gems/ruby-1.9.3-p194/gems/nokogiri-1.5.5 for inspection.
  Results logged to /usr/local/rvm/gems/ruby-1.9.3-p194/gems/nokogiri-1.5.5/ext/nokogiri/gem_make.out
  </code></pre>
  
  <p>Here are the contents of mkmf.log as requested:</p>
  
  <pre><code>package configuration for libxslt
  cflags: -I/usr/include/libxml2
  ldflags:
  libs: -lxslt -lz -lm -lxml2
  
  package configuration for libxml-2.0
  cflags: -I/usr/include/libxml2
  ldflags:
  libs: -lxml2
  
  package configuration for libiconv is not found
  "gcc -o conftest -I/usr/local/rvm/rubies/ruby-1.9.3-p194/include/ruby-1.9.1/x86_64-linux -I/usr/local/rvm/rubies/ruby-1.9.3-p194/include/ruby-1.9.1/ruby/backward -I/usr/local/rvm/rubies/ruby-1.9.3-p194/include/ruby-1.9.1 -I. -I/opt/local/include/libxml2 -I/usr/local/include/libxml2 -I/usr/local/rvm/rubies/ruby-1.9.3-p194/include/libxml2 -I/opt/local/include -I/usr/local/include -I/usr/local/rvm/rubies/ruby-1.9.3-p194/include -I/usr/include -I/usr/include/libxml2 -I/usr/local/rvm/usr/include     -O3 -ggdb -Wextra -Wno-unused-parameter -Wno-parentheses -Wno-long-long -Wno-missing-field-initializers -Wpointer-arith -Wwrite-strings -Wdeclaration-after-statement -Wimplicit-function-declaration  -fPIC  -g -DXP_UNIX -O3 -Wall -Wcast-qual -Wwrite-strings -Wconversion -Wmissing-noreturn -Winline -I/usr/include/libxml2   -I/usr/include/libxml2   conftest.c  -L. -L/usr/local/rvm/rubies/ruby-1.9.3-p194/lib -Wl,-R/usr/local/rvm/rubies/ruby-1.9.3-p194/lib -L/opt/local/lib -Wl,-R/opt/local/lib -L/usr/local/lib -Wl,-R/usr/local/lib -L/usr/local/rvm/rubies/ruby-1.9.3-p194/lib -Wl,-R/usr/local/rvm/rubies/ruby-1.9.3-p194/lib -L/usr/lib -Wl,-R/usr/lib -L/usr/local/rvm/usr/lib -Wl,-R/usr/local/rvm/usr/lib -L.  -rdynamic -Wl,-export-dynamic       -lxslt -lz -lm -lxml2   -lxml2   -Wl,-R -Wl,/usr/local/rvm/rubies/ruby-1.9.3-p194/lib -L/usr/local/rvm/rubies/ruby-1.9.3-p194/lib -lruby  -lpthread -lrt -ldl -lcrypt -lm   -lc "
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlGetLineNo@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlIsExtenderGroup@LIBXML2_2.6.0'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPathFreeContext@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlMalloc@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPathIsNodeType@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlStrchr@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlFreeDtd@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPathCtxtCompile@LIBXML2_2.6.5'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlSplitQName2@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlHashUpdateEntry@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPathEvalPredicate@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlRealloc@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPathContextSetCache@LIBXML2_2.6.25'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlFreeURI@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlAddPrevSibling@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlFindCharEncodingHandler@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlHashFree@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlSetProp@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `valuePop@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPathIsNaN@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlFreeIDTable@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlHashRemoveEntry2@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPtrEval@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPathNextAncestor@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPathInit@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlHashScan@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlOutputBufferCreateFd@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPathCompiledEval@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlHashAddEntry3@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPathFreeParserContext@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPathErr@LIBXML2_2.6.0'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlDictCreateSub@LIBXML2_2.6.5'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlDocSetRootElement@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPathObjectCopy@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlDictReference@LIBXML2_2.6.0'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPtrNewContext@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlNewText@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlNewComment@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlOutputBufferClose@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlBufferCat@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlNodeDumpOutput@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlHashLookup3@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlHasNsProp@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlIsDigitGroup@LIBXML2_2.6.0'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `htmlDocContentDumpOutput@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPathRegisterFunc@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlStrPrintf@LIBXML2_2.6.0'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlStrndup@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlSearchNs@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlNewDocNode@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlValidateQName@LIBXML2_2.5.4'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlMutexLock@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPathNodeSetAddUnique@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlValidateNCName@LIBXML2_2.5.4'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlNodeAddContent@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlGetID@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPathRegisterFuncLookup@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlFreeRefTable@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlStrdup@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlModuleSymbol@LIBXML2_2.6.17'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlHashUpdateEntry2@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlBufferFree@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlNewDocText@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlUnlinkNode@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlNewChild@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlNodeGetBase@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPathNodeSetMerge@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlMutexUnlock@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlFreeNode@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlStrstr@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlDictLookup@LIBXML2_2.6.0'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlGenericError@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlBufferWriteQuotedString@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlNewDocPI@LIBXML2_2.6.15'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlDocGetRootElement@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPathNumberFunction@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlIsBaseCharGroup@LIBXML2_2.6.0'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPathNewContext@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPathWrapNodeSet@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlNodeSetContent@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlGetIntSubset@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlParseURI@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlGetDtdAttrDesc@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlBufferAdd@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlParseDocument@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPathFreeNodeSet@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlHashCreate@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPathCastToString@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlCheckFilename@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `htmlDocContentDumpFormatOutput@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlNewMutex@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlLoadExternalEntity@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlModuleOpen@LIBXML2_2.6.17'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPathCompile@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `htmlNewDoc@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPathStringFunction@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlDocCopyNode@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlAddID@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlNewNs@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlNewParserCtxt@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPathConvertString@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlNewNsProp@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlGetDocEntity@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlNodeGetSpacePreserve@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPathOrderDocElems@LIBXML2_2.5.6'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPathNewParserContext@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlDictCreate@LIBXML2_2.6.0'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlFree@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPathRegisterFuncNS@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPathDebugDumpObject@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlDictQLookup@LIBXML2_2.6.0'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlGenericErrorContext@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPathEvalExpression@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `htmlNewDocNoDtD@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlHashLookup2@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlOutputBufferWriteString@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlOutputBufferCreateFilename@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlStrncat@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlStrlen@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlCharInRange@LIBXML2_2.6.0'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlNewDoc@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlAddChild@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlGetCharEncodingName@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPathRegisterVariableLookup@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPathFreeCompExpr@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPathNewCString@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlStrncasecmp@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXIncludeProcessFlags@LIBXML2_2.6.3'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlIsCombiningGroup@LIBXML2_2.6.0'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPathNodeSetCreate@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlHashScanFull@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `inputPush@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlStrEqual@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `valuePush@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlGetNsList@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlIsBlankNode@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlURIEscapeStr@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPathCmpNodes@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlCreateURI@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPathNextPrecedingSibling@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPathIsInf@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlDictFree@LIBXML2_2.6.0'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlBufferCCat@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPathCompiledEvalToBoolean@LIBXML2_2.6.27'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlOutputBufferCreateFile@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlSaveUri@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlNewDocProp@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlFreeParserCtxt@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlFreeMutex@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlNewDocNodeEatName@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPathNodeSetAdd@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlStringTextNoenc@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlSearchNsByHref@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPathStringEvalNumber@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlNewCDataBlock@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPathNewValueTree@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlBufferCreate@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlHashAddEntry2@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlFreeNodeList@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPathNewString@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlStringText@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPathEval@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlOutputBufferFlush@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlBufferContent@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPathNsLookup@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlGetProp@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlParserGetDirectory@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlUTF8Strloc@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlHashRemoveEntry@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPathFreeObject@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPathNewBoolean@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlUTF8Strpos@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlStrncmp@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlIsID@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPathFunctionLookupNS@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlCtxtUseOptions@LIBXML2_2.6.0'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlGetNsProp@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPathCastNodeToString@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlNewTextLen@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlNodeListGetString@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlHashAddEntry@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlAllocOutputBuffer@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlModuleClose@LIBXML2_2.6.17'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlSetNsProp@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPathConvertNumber@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlStrcasecmp@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlNodeGetContent@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlStrcmp@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlCreateIntSubset@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlFreeDoc@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlCopyCharMultiByte@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlHashUpdateEntry3@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlDictOwns@LIBXML2_2.6.0'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlStrcat@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlStringCurrentChar@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlXPathNewNodeSet@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `htmlSetMetaEncoding@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlHashLookup@LIBXML2_2.4.30'
  /usr/local/rvm/usr/lib/libxslt.so: undefined reference to `xmlBuildURI@LIBXML2_2.4.30'
  collect2: ld returned 1 exit status
  checked program was:
  /* begin */
  1: #include "ruby.h"
  2:
  3: int main() {return 0;}
  /* end */
  </code></pre>