Macros PAGE_OFFSET, KERNELBASE, LOAD_OFFSET defined in arch/powerpc/include/asm/page.h (and probably others) are not seen as macros for powerpc.
https://elixir.bootlin.com/linux/v6.16/A/ident/PAGE_OFFSET
https://elixir.bootlin.com/linux/v6.16/A/ident/LOAD_OFFSET
https://elixir.bootlin.com/linux/v6.16/A/ident/KERNELBASE
Looks more or less similar to #278 . By the way the problem is still there as well for that one, see https://elixir.bootlin.com/linux/v6.16/A/ident/__WARN_FLAGS