code: function loadConfigGypi () {
      var configPath = path.resolve('build', 'config.gypi')
      fs.readFile(configPath, 'utf8', function (err, data) {
        if (err) {
          if (err.code == 'ENOENT') {
            callback(new Error('You must run `node-gyp configure` first!'))
          } else {
            callback(err)
          }
          return
        }
        config = JSON.parse(data.replace(/\#.+\n/, ''))
  
        // get the 'arch', 'buildType', and 'nodeDir' vars from the config
        buildType = config.target_defaults.default_configuration
        arch = config.variables.target_arch
        nodeDir = config.variables.nodedir
  
        if ('debug' in gyp.opts) {
          buildType = gyp.opts.debug ? 'Debug' : 'Release'
        }
        if (!buildType) {
          buildType = 'Release'
        }
  
        log.verbose('build type', buildType)
        log.verbose('architecture', arch)
        log.verbose('node dev dir', nodeDir)
  
        if (win) {
          findSolutionFile()
        } else {
          doWhich()
        }
      })
    }
docs: Load the "config.gypi" file that was generated during "configure".