"can't find kernel source tree" error when building the kernel.

hello,

i just downloaded via cvsup the latest kernel for freebsd 5.1.
i had a problem with it, more exactly when i did a "make depend"
it stopped at some place, and gave me this error:
"can't find kernel source tree"
i fixed this by modifying this piece of code from /usr/src/sys/conf/kmod.mk
(it starts with line 167 in the file)

.for _dir in ${.CURDIR}/../.. ${.CURDIR}/../../.. /sys /usr/src/sys
.if !defined(SYSDIR) && exists(${_dir}/kern/)
SYSDIR= ${_dir}
.endif
.endfor
.if !defined(SYSDIR) || !exists(${SYSDIR}/kern/)
.error "can't find kernel source tree"
.endif

i removed the last "/" from "/kern/" and now it seems it can find the 
directory.
i don't know if this is a general problem, or it is just in the case of 
my system.

Claudiu Dragalina-Paraipan.
clau_at_reversedhell.net