title: Unable to find dnssd headers error while trying to install a ruby gem
body: <p>Getting this error</p>
  
  <pre><code>ERROR:  Error installing dnssd:
  ERROR: Failed to build gem native extension.
  
  /Users/me/.rvm/rubies/ruby-1.9.3-p550/bin/ruby -r ./siteconf20141108-39945-13la3bu.rb extconf.rb
  checking for dns_sd.h... no
  unable to find dnssd header
  *** extconf.rb failed ***
  
  Gem files will remain installed in /Users/me/.rvm/gems/ruby-1.9.3-p550@kevy/gems/dnssd-2.0 for inspection.
  Results logged to /Users/me/.rvm/gems/ruby-1.9.3-p550@kevy/extensions/x86_64-darwin-14/1.9.1/dnssd-2.0/gem_make.out
  An error occurred while installing dnssd (2.0), and Bundler cannot continue.
  Make sure that `gem install dnssd -v '2.0'` succeeds before bundling.
  </code></pre>
  
  <p>I'm running yosemite osx so the header file is there by default. I found it at /usr/include/dns_sd.h.</p>
  
  <p>Short of reinstalling operating system is there any way to fix?</p>
  
  <p>Thanks</p>