The GNU Developpement Chain supports all variants of 68HC11, 68HC12 and 68HCS12 micro-controllers.
There is no dependency on any board. This means you can use the tool chain to develop on any board based on a 68HC11, 68HC12 or 68HCS12.
When you develop for a particular board, you must write a memory.x file which describes the memory (RAM and ROM) of the board.
If your board has particular external IOs, you may have to write the support to access and control your specific devices. This can be done in C quite easily.