• cd to each target and verify:
  • $(git rev-parse HEAD) == .gitmodules for the path
  • $(git status --porcelain | wc -l) == 0
  • That the build exits in $repo
  • If any of these checks fail, rebuild and mark following stages for rebuild. (TODO: dont invalidate whole stages, only what must be invalidated)
• cd to target, and run commands in order. If any of them fail, do not continue the build, or push anything to the repo. Builds from a single stage could be done in parallel, based on load average (or something else?)
• deliver contents of gbuild.out/ to $repo