I don't need some fancy atomic output file updating or
posix_fadvise. I removed all platform-specific code
except for a single `chmod`.
That's not to say there's no advantage to atomically
reading or writing files, but for this project, the first
rule needs to be KISS. It's premature optimization and
overengineering.
Now we always use the stack instead of keeping a TOS register.
This is very inefficient, but I'll worry about register
allocation later.
The new block model is inspired by x86's `enter` and `leave`
instructions. I intend to support nested procedures at some point
in the future.
James T. Martin