I suspect--but have no way to test--that there is a subtle difference
in game play between perm_invent and !perm_invent involving object merging
or other activity that depends on whether or not object->dknown is set.
For objects pickup up while blind, where object->dknown is left as is,
the perm_invent config would have such items marked as seen sooner (since
there are umpteen places that call update_inventory() which will end up
setting the seen bit while formatting objects). Non-perm_invent wouldn't
have that done until the user examines invent (or asks to see a list of
objects at the "which object?" prompt for various commands). This patch
effectively examines inventory whenever blindness ends, so both modes get
dknown set as soon as possible. And if we ever add an "effect known" flag
for unseen objects which are used while blind, this would be a suitable
place to perform deferred object discovery.
fb043c5f01