index.js
function gnuMessage(message, source) {
  return (source ? (source.file ? source.file : "<css input>") + ":" + source.start.line + ":" + source.start.column : "") + " " + message
}
function gnuMessage(message, source) {
  return (source ? (source.file ? source.file : "<css input>") + ":" + source.start.line + ":" + source.start.column : "") + " " + message
}
function gnuMessage ( message , source ) { return ( source ? ( source . file ? source . file : "<css input>" ) + ":" + source . start . line + ":" + source . start . column : "" ) + " " + message }
return GNU style message

@param {String} message
@param {Object} source
return GNU style message