Amiga GDB Debugging
Debugging AmigaOS with the AROS GDB Utilities
You can use C:GDBStub and C:GDBStop from aros-m68k-system.iso - it runs on not only AROS, but also KS 1.3 ... KS 3.x, and uses the serial port for the debug port.
C:GDBStub is a self-detaching program, and installs hooks into Exec/Alert(), the TRAP vectors, and every newly run program's default tc_TrapHook. When those hooks trigger, it starts up a GDB Stub target on the serial port.
(You can use C:GDBStop to start a GDB Stub session manually)
You can then use a m68k-elf-gdb on your host with the 'target remote /dev/ttyS0' (if using a physical serial port) or 'target remote localhost:1234' (if using an emulator) command to make a local connection to the emulator's serial port.
NOTE: When using C:GDBStop, you'll need to 'set $pc=$pc+2' to skip over the 'trap #1' instruction before continuing execution.