The functions add_dependencies() and set_global() are convenience
methods that allow you to modify the global namespace while
the current file is running but then have it be cleaned up
by index.js when you're done.
(imported from commit f75b8a10c19f773a8d2d3a8fa4bc39b1679566fe)
There are also one or two places we don't need to use it for security
purposes, but we do so for consistencey.
(imported from commit aa111f5a22a0e8597ec3cf8504adae66d5fb6768)
Steve Howell
Leo Franchi
Zev Benjamin