ext2fs build error

Custom board derived from Altera High Speed board with 16MB FLASH, 16MB SDRAM (for kernel and root fs), and 512MB DDR2 SDRAM for large vector file storage in pattern generator application.

Need to mount an ext2fs on ramdisks in DDR2, but get build error when ext2fs file applications are added to configuration. ext2fs support is enabled in kernel.

Kernel is uClinux-dist from wiki, with patch (applied only once) and compiled with binary toolchain on RedHat EW V4 machine specific for this project.

Specific error:

In function `init_resource_track':

.../user/e2fsprogs/e2fsck/util.c:217 undefined reference to `sbrk'

another undefined reference to `sbrk', and

In function `ext2fs_llseek':

.../user/e2fsprogs/lib/ext2fs/llseek.c:102: undefined reference to `llseek'

I'm a hardware guy, and I have battled many many problems along the way to getting an embedded user interface running as a cgi application served up by fnord. Please let me know what the process for working around kernel build errors. Thank you.