ccdef was broken by the following commit:
commit 7d748dc6e2
Author: ggn <ggn@atari.org>
Date: Thu Mar 24 13:28:09 2022 +0200
Fix for #159: Split register sets according to architecture into
different tables so they don't clash with label/symbol names.
Modified tokeniser to use different tables when scanning for
registers
This change fixes it by moving the ccdef and .ccdef
tokens from the unary table to the keyword table.