[U-Boot] curious about "#ifndef CONFIG_ENV_OVERWRITE" test in lsxl.c

was perusing the wiki page on u-boot environment variables:

http://www.denx.de/wiki/view/DULG/UBootPowerOn

and just now learned about the ability to mark environment variables as "set once", that sort of thing, so i went looking for examples, and noticed, in board/buffalo/lsxl/lsxl.c:

#ifndef CONFIG_ENV_OVERWRITE # error "You need to set CONFIG_ENV_OVERWRITE" #endif

ok, but why not just add the line:

#define CONFIG_ENV_OVERWRITE

to include/configs/lsxl.h, and get rid of that test? or is this just a historical holdover when things were done differently?

rday