New Drush install instructions use Composer for install, even on Drupal 7? The current Github install instructions for drush (http://docs.drush.org/en/master/install/#git-clone-ie-manual-install) say as the last step:


  From Drush root, run Composer to fetch dependencies.
  
  $ composer install


Since Drupal 7 does not usually have Composer installed, I assume these are Drupal 8 specific instructions.

Where can I find a link to instructions for installing Drush for a Drupal 7 install, where composer is not present?
Drush uses composer to install its dependencies, so please follow the composer instructions regardless of whether you plan to use drush with Drupal 7 or Drupal 8.