code: func globalPluginDirs() []string {
  	var ret []string
  	// Look in ~/.terraform.d/plugins/ , or its equivalent on non-UNIX
  	dir, err := ConfigDir()
  	if err != nil {
  		log.Printf("[ERROR] Error finding global config directory: %s", err)
  	} else {
  		machineDir := fmt.Sprintf("%s_%s", runtime.GOOS, runtime.GOARCH)
  		ret = append(ret, filepath.Join(dir, "plugins"))
  		ret = append(ret, filepath.Join(dir, "plugins", machineDir))
  	}
  
  	return ret
  }
docs: // globalPluginDirs returns directories that should be searched for
  // globally-installed plugins (not specific to the current configuration).
  //
  // Earlier entries in this slice get priority over later when multiple copies
  // of the same plugin version are found, but newer versions always override
  // older versions where both satisfy the provider version constraints.