anchor.diff:  , withPam ? false, pam
   , withZlib ? true, zlib
   , withRiak ? false
  -, withElixir ? false, elixir
   , withIconv ? true
   , withTools ? false
   , withRedis ? false
  
positive.code:   preBuild = ''
      cp -r $deps deps
      chmod -R +w deps
      patchShebangs deps
    '';
  
    postInstall = ''
  
negative.code:     homepage = "https://www.ejabberd.im";
      platforms = platforms.linux;
      maintainers = with maintainers; [ sander abbradar ];
    };
  }
  