anchor.diff:  
   writeScript "update-${attrPath}" ''
     #!${runtimeShell}
  -  PATH=${lib.makeBinPath [ common-updater-scripts coreutils curl gnugrep gnused xidel ]}
  +  PATH=${lib.makeBinPath [ common-updater-scripts coreutils curl gnugrep gnupg gnused xidel ]}
  +
  +  set -eux
  +  HOME=`mktemp -d`
  +  export GNUPGHOME=`mktemp -d`
  +  gpg --import ${../firefox-bin/mozilla.asc}
   
     url=${baseUrl}
   
  
positive.code:            sort --version-sort | \
             tail -n 1`
  
    update-source-version ${attrPath} "$version" "" "" --version-key=${versionKey}
  ''
  
negative.code: , gnused
  , gnugrep
  , curl
  , gnupg
  , attrPath
  , runtimeShell
  , baseUrl ? "http://archive.mozilla.org/pub/firefox/releases/"
  