sys directory link reset by an installkernel

I have my FreeBSD checked out in a non-standard location.  I have then
set /sys to point to the sys directory for this non-statndard
location.  But eveytime I perform an installkernel, this link is
changed to sys -> usr/src/sys.  This causes problems when I need to
build a port that requires the Kernel src files.

My layout is as follows:

ls /
/
:
sys -> usr/src/5x/sys
:

ls /usr/src
4x
5x
6x
sys -> /sys

With the above layout, I can NFS mount /usr/src on my 4x, 5x, and 6x
systems and not have to make sure that /usr/src/sys points to the
correct source tree.

I have fixed this problem on my system by using the patch in the following PR

http://www.freebsd.org/cgi/query-pr.cgi?pr=76362

The patch will set the /sys link to the correct location of the
sources during a installkernel.

Scot