[U-Boot] undefine reference to `__bss_end__' error

Hi all.

I'm trying to upgrade my u-boot from 16 May 2009 release (out of tree customized version) to the release version December 2011. This is for powerpc MPC8349. I feel I’m very close to having U-boot successfully built, but I’m getting a symbol error at the end of the final link:

arch/powerpc/cpu/mpc83xx/start.o:(.got2+0x8): undefined reference to `__bss_end__' arch/powerpc/lib/libpowerpc.o:(.got2+0x54): undefined reference to `__bss_end__'

I googled around and saw (perhaps unrelated) that in some cases, the symbol `__bss_end__' may not be defined. So, in /arch/powerpc/mpc83xx/Start.s and arch/powerpc/lib/board.c, I manually changed `__bss_end__' to `_end'. However, I now get the following error:

arch/powerpc/cpu/mpc83xx/start.o:(.got2+0x8): undefined reference to `_end' arch/powerpc/lib/libpowerpc.o:(.got2+0x54): undefined reference to `_end'

So, my question is, is my problem a basic definition of these symbols, and if so, how to define `__bss_end__' or ‘_end’? (and where is the best place to put the definition)?

Thanks in advance, Will