It would be nice if we could add a file version.h, which is autogenerated for git builds, and static for source tarballs, with the output of "git describe" as contents. This command gives as output:

• the latest git tag reachable from the current commit
• (if any commits since that tag) the number of such commits
• (if any commits since that tag) the latest commit id

That output could be used as a "build id", available via getinfo or the about box.