r6417: Strange old IRIX systems return -1 for telldir() when

r6417: Strange old IRIX systems return -1 for telldir() when
end of directory reached. Don't check for that and bail
when reading directory entries as it's a valid value.
Excellent work from Cale Fairchild <cale@brocku.ca>
tracked this down.
Jeremy.
(This used to be commit a60fe9aba16eac4f195a2359d8b7672d8c8aa240)