title: facing error while installing sudo gem install cocoapods in Xcode 11.3.1
body: <p><strong>Error : <em>in terminal</em></strong></p>
  <blockquote>
  <p>Building native extensions.  This could take a while...
  ERROR:  Error installing cocoapods:
  ERROR: Failed to build gem native extension.</p>
  <pre><code>    current directory: /Users/cirightios2/.gems/gems/ffi-1.13.1/ext/ffi_c
  /System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/bin/ruby -r
  </code></pre>
  <p>./siteconf20200702-3272-1prph8d.rb extconf.rb
  mkmf.rb can't find header files for ruby at /System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/include/ruby.h</p>
  <pre><code>extconf failed, exit code 1
  
  Gem files will remain installed in /Users/cirightios2/.gems/gems/ffi-1.13.1 for inspection.
  Results logged to /Users/cirightios2/.gems/extensions/universal-darwin-18/2.3.0/ffi-1.13.1/gem_make.out
  </code></pre>
  </blockquote>