So far only basic debugging functionality is implemented (breakpoints,
stepping, stack traces/variables).
This is not tested against an established DAP client. My intention is to
create a custom GUI frontend and extend the protocol to support
xsystem4-specific features, such as inspecting the scene. (This work is
underway.)
Instruction references are hex-encoded address strings. Clients do not
need to obtain them from DAP requests. This is outside the spec, but it
is needed for a binary-only debugger.
Functions that write directly to stdout (e.g. printf) should generally
not be used any more. Instead, use either sys_message (which respects
sys_silent) or log_message (which will send the message to the debugger
if DAP is enabled). stderr can be used as normal.
