Error: ‘none’ undeclared (first use in this function). drivers/src/librsu_cfg.c:87:20: note: in expansion of macro ‘RSU_PROTECTION_SLOT’

This error might be seen during the Nios® II processor software compilation in the Quartus® Prime Pro Edition Software version 22.3.  

It affects Nios ® II processor system designs that: 

1. Instantiate the Mailbox Client FPGA IP.

2. Generate a new Board Support Package. 

The error is seen because the Nios II processor software public.mk file wrongly reflects the RSU_PROTECTION_SLOT variable. 

To work around this problem, open the Nios® II processor software public.mk file and comment the parameter as shown below. 

#ALT_CPPFLAGS += -DRSU_PROTECTION_SLOT=none