There should be a way to search for duplicate names or paths without regard to case. A common way for this to occur is when someone on a windows or other less case sensitive system handled the files, or someone changed file extension case to better match some web server.
Making case insensitive comparison the only option would simply mean replacing two strcmp with strcasecmp in dupe.c. A patch for this is attached.
If you want both, case sensitive and case insensitive comparison, that would require a bit more work, but I guess that's not worth the effort.