Several files have kernel_version defined in them. I found
drivers/char/lp.c, drivers/net/ppp.c, slhc.c, and slip.c, and
drivers/sound/soundcard.c along with references in all of the card
files.
I understand the idea of one central statement in modules.h as opposed
to varying instances (e.g., inside and out of ifdef's) throughout the
kernel driver files and encourage revisions of the files listed above
instead of modifying module.h (which is what I used to compile
1.3.38).
Rick