- distinguish between unmapped and 0-length output strings
- don't do any processing for 0-length output strings
- no change to developer, that will be next
- remove a comment referencing transform=no
For: #9451
- lookup needs to handle either/neither/both cases for alt and ctrl
- and a bug in the test runner: would 'pass' if failed on exactly line 256 (0x100 & 0xFF == 0)
#7533