Improve sudo need

Right now the Tor Browser build takes a long time, and sudo is needed periodically throughout it. This means you have to either run it as root, babysit it, or set your user account up with passwordless sudo. All of those kinda stink.

It's be cool if we could improve that a bit. Ideas:

• Write a setuid program that execs the necessary commands but provides input and directory filtering (directory path either compiled in or read from a root-owned file I guess)
• Same idea but instead of setuid, it's set up to be run with passwordless sudo
• Somehow request sudo access in the beginning and retain it through the whole script (without running everything as root)