anchor.diff:      ${optionalString withRuby_2_4   "./configure ruby   --module=ruby24   --ruby=${ruby_2_4}/bin/ruby"}
       ${optionalString withRuby_2_5   "./configure ruby   --module=ruby25   --ruby=${ruby_2_5}/bin/ruby"}
       ${optionalString withRuby_2_6   "./configure ruby   --module=ruby26   --ruby=${ruby_2_6}/bin/ruby"}
  +    ${optionalString withRuby_2_7   "./configure ruby   --module=ruby27   --ruby=${ruby_2_7}/bin/ruby"}
     '';
   
     meta = {
  
positive.code:     ++ optional withRuby_2_4 ruby_2_4
      ++ optional withRuby_2_5 ruby_2_5
      ++ optional withRuby_2_6 ruby_2_6
      ++ optional withSSL openssl;
  
    configureFlags = [
  
negative.code: , withRuby_2_4 ? false, ruby_2_4
  , withRuby_2_5 ? false, ruby_2_5
  , withRuby_2_6 ? true, ruby_2_6
  , withRuby_2_7 ? true, ruby_2_7
  , withSSL ? true, openssl ? null
  , withIPv6 ? true
  , withDebug ? false
  