Add lazy github download support to drush make. This has been tested with drush make 5.8. It may work on earlier versions, but I haven't tested it.

example.make

; Example drush make file using the github download type.

api = 2
core = 7

projects[] = drupal

; Module
projects[bean_boxes][type] = "module"
projects[bean_boxes][download][type] = "github"
projects[bean_boxes][download][url] = "skwashd/bean_boxes"

; Library
projects[gitter][type] = "library"
projects[gitter][download][type] = "github"
projects[gitter][download][url] = "klaussilveira/gitter"

github.drush.inc

<?php

/**
 * Github download support functions for drush make.
 */

/**
 * Support lazy downloads from github.
 */
function make_download_github($name, $download, $download_location) {
  $download['url'] = "git@github.com:{$download['url']}.git";
  return make_download_git($name, $download, $download_location);
}