Is this project still maintained?

[ApplebaumIan]

Hi,
I’m attempting to create a simulator for GRBL for my project, but compilation yields numerous errors.

1.319 grbl_interface.c:84:6: error: ‘SPINDLE_TCCRA_REGISTER’ is undeclared (first use in this function); did you mean ‘TCCRA_REGISTER’?
1.319    84 |   if(SPINDLE_TCCRA_REGISTER >= 127) ocr = SPINDLE_OCR_REGISTER;
1.319       |      ^~~~~~~~~~~~~~~~~~~~~~
1.319       |      TCCRA_REGISTER
1.319 grbl_interface.c:84:6: note: each undeclared identifier is reported only once for each function it appears in
1.320 grbl_interface.c:84:43: error: ‘SPINDLE_OCR_REGISTER’ is undeclared (first use in this function)
1.320    84 |   if(SPINDLE_TCCRA_REGISTER >= 127) ocr = SPINDLE_OCR_REGISTER;
1.320       |                                           ^~~~~~~~~~~~~~~~~~~~
1.321 grbl_interface.c:94:75: error: ‘sys_position’ is undeclared (first use in this function); did you mean ‘block_position’?
1.321    94 |      fprintf(args.step_out_file, “%12.5f %d, %d, %d, %d\n”, sim.sim_time, sys_position[X_AXIS], sys_position[Y_AXIS], sys_position[Z_AXIS],ocr);
1.321       |                                                                           ^~~~~~~~~~~~
1.321       |                                                                           block_position
1.322 make: *** [Makefile:64: grbl_interface.o] Error 1

I attempted to fork the project to see if I could easily modify any of these, but I keep finding myself down a rabbit hole of many parts of this repository that are out of sync with the main GRBL repository.

By the way, does anyone else have a way to emulate GRBL without using an Arduino, or is it simply the de facto method for developing on this platform? Any information would be greatly appreciated.

Best regards,
Ian