TMI: A little less stuck on rustpkg

[tim]

Today:

• Did my Monday randomly-assigned-bug triage.
  
• Tried again to get some test-case pull requests to pass.
  
• Learned about build automation from Graydon.
  
• Almost finished up extern-mod inference for rustpkg. I really wish I could say that I finished it and not that I almost finished it, but I got all my automated tests to pass (something I've been trying to do for days)... and then found that my one manual test didn't work, because I'd changed the expected directory format again without really thinking about it. I look forward to having only automated tests, but the test runner is a separate issue. Though, the more I think about it, the less I'm sure I need to write a special test runner for rustpkg -- maybe it would be enough just to have unit tests that use os::set_args and then call into rustpkg's main.