Cactus doesn't handle well adding or removing configuration.ccl files. When a new configuration.ccl file is added, Cactus ignores it until the next "rebuild" (i.e. until another ccl file changes, until the thorn list changes, or until the user calls *-rebuild explicitly). When a configuration.ccl file is removed, make aborts with an error message, and a rebuild is forced.
One way to remedy this would be to have (empty) configuration.ccl file in all thorns. After all, param.ccl and schedule.ccl files also need to be present even if they are empty. This would also remove a bit of complex logic from the Cactus make system.