[project @ 2000-04-04 15:41:56 by sewardj]
* Enforce downward closure rule (first attempt :-)
If both object and source of a module are available, be simple and
choose the more recent. If that causes a subsequent violation of the
DCR, complain to the user at the time the violation is detected.
The alternative is to have a clever algorithm which makes clever
choices now to avoid conflicts later, but that looks complicated to
do, and I think it would also confuse users.
* As a side effect of the above, enforce the rule that the Prelude
must be all source or all object, but not a combination.
* Rationalise signature and semantics for findFilesForModule, so as to
make client code simpler.