might allow goals to be called with labelled parameters.
Deleting target files if goals is interrupted, but only if the
-timestamp changes (what about non-*files?). Also: atomic code. This
-will delete the target if the code doesn't run to completion. (make
-doesn't do this, but probably it should).
+timestamp changes (what about things which are not is-files?).
+Also: atomic code. This will delete the target if the code
+doesn't run to completion. (make doesn't do this, but
+probably it should).
Conditional sections (same as "ifeq" etc in make).