Error during making of kernel-rt

I’m doing a real time kernel for my opensuse running on a PPC ibook G4, when i do “make” after some time this error arrived:

CC arch/powerpc/kernel/crash_dump.o
cc1: warnings being treated as errors
arch/powerpc/kernel/crash_dump.c: In function ‘copy_oldmem_page’:
arch/powerpc/kernel/crash_dump.c:131: error: comparison of distinct pointer types lacks a cast
make[1]: *** [arch/powerpc/kernel/crash_dump.o] Error 1
make: *** [arch/powerpc/kernel] Error 2

What can be?