This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.
Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.
2. Clean up code so it compiles -Wall (except for sccsid's and copyright).
This included fixing several printf formats that where not correct,
and changing the data types of a few things.
3. Implement new option -i that produces indented mtree output files.
4. Implement new option -n that turns off directory comments.
5. Only emit /set records if something has changed since the last one.