This involved breaking things up into more segments in debug mode, since the code is larger. I also had to remove some unused extern definitions, which were causing link errors when debug code was enabled.
To enable debug code, pass "DEBUG=1" to make or build.gs.
Dmake gets confused if you use over-15-character file names, so they needed to be shortened to get it to work. While I was at it, I also switched _ to . in the filenames so they're fully ProDOS compatible.
The shell/hush_test directory (not needed to build the code) still uses ProDOS-incompatible file names.
