title: extconf failed, exit code 1 error when installing [Ruby on Rails] 5 on OS X Yosemite 10.10.5
body: <p>I'm trying to install Ruby on Rails v5 on OS X Yosemite 10.10.5, following the instructions on the rails site:</p>
  
  <p><a href="http://railsapps.github.io/installrubyonrails-mac.html" rel="noreferrer">http://railsapps.github.io/installrubyonrails-mac.html</a></p>
  
  <p>When I run this:</p>
  
  <pre><code>sudo gem install rails --version 5.0.0 --no-ri --no-rdoc
  </code></pre>
  
  <p>I get the error <code>ERROR: Failed to build gem native extension</code>. 
  Here are parts of the output on my command line that might be useful:</p>
  
  <pre><code>current directory: /Users/me/.rvm/rubies/ruby-2.3.0/lib/ruby/gems/2.3.0/gems/nokogiri-1.6.8/ext/nokogiri
  
  [...]
  
  
  Running 'compile' for libxml2 2.9.4... ERROR, review '/Users/me/.rvm/rubies/ruby-2.3.0/lib/ruby/gems/2.3.0/gems/nokogiri-1.6.8/ext/nokogiri/tmp/x86_64-apple-da
  
  rwin14.5.0/ports/libxml2/2.9.4/compile.log' to see what happened. Last lines are:
  
  [...]
  
   1 error generated.
      make[2]: *** [xmlIO.lo] Error 1
      make[1]: *** [all-recursive] Error 1
      make: *** [all] Error 2
      ========================================================================
      *** 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.
  
  [...]
  
      To see why this extension failed to compile, please check the mkmf.log which can be found here:
  
        /Users/me/.rvm/rubies/ruby-2.3.0/lib/ruby/gems/2.3.0/extensions/x86_64-darwin-14/2.3.0/nokogiri-1.6.8/mkmf.log
  
  
      extconf failed, exit code 1
  </code></pre>
  
  <p>And here's part of the mkmf.log file:</p>
  
  <pre><code>"gcc -o conftest -I/Users/me/.rvm/rubies/ruby-2.3.0/include/ruby-2.3.0/x86_64-darwin14 -I/Users/me/.rvm/rubies/ruby-2.3.0/include/ruby-2.3.0/ruby/backward -I/Users/me/.rvm/rubies/ruby-2.3.0/include/ruby-2.3.0 -I.  -I/usr/local/opt/libyaml/include -I/usr/local/opt/readline/include -I/usr/local/opt/libksba/include -I/usr/local/opt/openssl/include -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE -D_DARWIN_UNLIMITED_SELECT -D_REENTRANT    -O3 -fno-fast-math -ggdb3 -Wall -Wextra -Wno-unused-parameter -Wno-parentheses -Wno-long-long -Wno-missing-field-initializers -Wunused-variable -Wpointer-arith -Wwrite-strings -Wdeclaration-after-statement -Wshorten-64-to-32 -Wimplicit-function-declaration -Wdivision-by-zero -Wdeprecated-declarations -Wextra-tokens  -fno-common -pipe  conftest.c  -L. -L/Users/thanos/.rvm/rubies/ruby-2.3.0/lib -L/usr/local/opt/libyaml/lib -L/usr/local/opt/readline/lib -L/usr/local/opt/libksba/lib -L/usr/local/opt/openssl/lib -L. -fstack-protector -L/usr/local/lib -L/usr/local/opt/libyaml/lib -L/usr/local/opt/readline/lib -L/usr/local/opt/libksba/lib -L/usr/local/opt/openssl/lib     -lruby.2.3.0  -lpthread -ldl -lobjc  "
  /Users/me/.rvm/rubies/ruby-2.3.0/lib/ruby/2.3.0/mkmf.rb:395: warning: Insecure world writable dir /usr/local/bin in PATH, mode 040777
  checked program was:
  /* begin */
  1: #include "ruby.h"
  2:
  3: int main(int argc, char **argv)
  4: {
  5:   return 0;
  6: }
  /* end */
  </code></pre>
  
  <p>I have no idea what is going on :(. Can someone help?</p>
  
  <p>RUBY VERSION: 2.3.0p0.
  RUBYGEMS VERSION: 2.5.1</p>
  
  <p>xcode-select is successfully installed.</p>
  
  <p>Thanks!</p>