[m-dev.] For review: improve undefined pred/symbol error message

[Thomas Charles CONWAY]

Fergus Henderson, you write:
> You don't need to take sub-modules into account,
> but you do need to take parent modules into account.
> So that diff is still not right.

There is no `import_status' value that indicates symbols
inherited from a parent module. How do you determine them?
Is the solution just to check to see if the given module
qualifier is a parent of any of the current module?

BTW, this change only improves an error message, so it is 'correct'
in some sense without handling sub-modules correctly - it just isn't
as helpful as it could be, so if handling sub-modules correctly
turns out to be very nasty, rather than being a bug it could quite
happily be an unimplemented feature. :-)

-- 
Thomas Conway <conway at cs.mu.oz.au>
Nail here [] for new monitor.  )O+