Most code in keymap.h is for keycode definitions, while most code in
keymap.c is for the parsing and conversion of keycodes.
The name "keymap" may also make people think these two files are for
mappings, while in fact keycodes are used even when no mappings are
involved, so "keycodes" should be a better file name than "keymap".
First stage: something compiling without klee, but with a buch of dirty
hacks - done.
Second stage: something running under klee, able to emit useful results,
but still using dirty hacks - done.
Third stage: make CMake care about clang argumnets - not done, may be
omitted if proves to be too hard. Not that klee can be run on CI in any
case.
