- Option was recently added but never released.
- Custom commands no longer depend on build.make so we do
not need the option.
- Rule hashes now take care of rebuilding when rules change
so the dependency is not needed.
- Allows make rules to be created with no dependencies.
- Such rules will not re-run even if the commands themselves change.
- Useful to create rules that run only if the output is missing.
Brad King
Ken Martin