Managing Local Changes with Mercurial Queues

gem5 users typically opt to freeze their repository at a particular changeset when starting a new research project. This is understandable because, oftentimes the changes they make for their project aren't likely to be contributed back to the main repository, and keeping the source tree up-to-date is tedious given the speed at which gem5 changes. However, this approach has several downsides:

• It discourages users from contributing back useful changes.
• If a useful change is added, it's a long, tedious process to update.