message: Set OS name as "darwin" for MacOS instead of "osx"
  (to use same semantics as in package.json)
diff: module.exports = function (grunt) {
  var node = grunt.option('node') || process.env.nodejs_version || process.env.TRAVIS_NODE_VERSION || ''
  var platform = grunt.option('platform') || process.env.TRAVIS ? 'x64' : ''
  - var os = grunt.option('os') || process.env.TRAVIS_OS_NAME === 'windows' ? 'win32' : (process.env.TRAVIS_OS_NAME || '')
  + var os = grunt.option('os') || process.env.TRAVIS_OS_NAME === 'windows' ? 'win32' : (process.env.TRAVIS_OS_NAME === 'osx' ? 'darwin' : (process.env.TRAVIS_OS_NAME || ''))
  grunt.initConfig({
  pkg: grunt.file.readJSON('package.json'),
  