title: sudo gem instal sass giving me this error: ERROR: Failed to build gem native extension
body: <p>I am trying to install Sass using <code>sudo gem install sass</code> on my Mac terminal. It gives me this error:</p>
  <pre><code>Building native extensions. This could take a while...
  ERROR:  Error installing sass:
      ERROR: Failed to build gem native extension.
  
      current directory: /Library/Ruby/Gems/2.6.0/gems/ffi-1.14.2/ext/ffi_c
  /System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/bin/ruby -I /System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/lib/ruby/2.6.0 -r ./siteconf20210118-51317-14a8oi4.rb extconf.rb
  *** 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
      --without-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=/System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/bin/$(RUBY_BASE_NAME)
      --with-ffi_c-dir
      --without-ffi_c-dir
      --with-ffi_c-include
      --without-ffi_c-include=${ffi_c-dir}/include
      --with-ffi_c-lib
      --without-ffi_c-lib=${ffi_c-dir}/lib
      --enable-system-libffi
      --disable-system-libffi
      --with-libffi-config
      --without-libffi-config
      --with-pkg-config
      --without-pkg-config
  /System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/lib/ruby/2.6.0/mkmf.rb:467:in `try_do': The compiler failed to generate an executable file. (RuntimeError)
  You have to install development tools first.
      from /System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/lib/ruby/2.6.0/mkmf.rb:546:in `block in try_link0'
  </code></pre>
  <p>For reference, my operating system is macOS Catalina version 10.15.7 and I have ruby 2.6.3p62. I have tried <code>sudo apt install ruby-dev</code> before trying to again, and it gives me this message:</p>
  <pre><code>Unable to locate an executable at &quot;/Library/Java/JavaVirtualMachines/jdk-15.0.1.jdk/Contents/Home/bin/apt&quot; (-1). 
  </code></pre>
  <p>I have also tried installing with brew and I already have command line tools installed. What should I do?</p>