3023
3024
3025 - switch to current tracing

I'd like to explore decomposing this mouthful at some point, but it's a
special-case for now: all the code shows up with globals.

I tried various ways of separating the tracing types from the globals
from the macros from the code, but in the end the only easy solution I
could find was what the existing repo does: keep all tracing code before
main and test harness.
3026

Make the hacky special-case more apparent.
3027 - start on tokenize, including our first test