Attached are two related 'grep' patches, one prompted by Bug#33552 "Possible bug 
with handling -I option" and the other by Bug#29668 "grep: Fatal problem with 
(big) file". Although I'd normally install these on grep master, Jim has started 
the ball rolling on the next grep release so I'll cc this to him to see whether 
these patches can be squeezed in before the next release.