good luck trying to build that program it was written for an older gcc compiler. so you see it is not your machine or the software
cc -Wall -O2 -Wstrict-prototypes -fomit-frame-pointer -pipe -fno-strength-reduce -falign-loops=2 -falign-jumps=2 -falign-functions=2 -include /usr/src/linux-2.6/include/linux/modversions.h -I/usr/src/linux-2.6/include -Wno-uninitialized -c src/modhide.c -c src/knark.c -o knark.c -D__KERNEL__ -DMODULE -DMODVERSIONS
cc: cannot specify -o with -c or -S with multiple files
this just says the newer gcc or cpp compiler headers will not work. If I was you I would install a separate gcc like 3.2 you system is using 4.3 I think. it will not build the old programs. then you will may run into other problems trying to run it on your system.
Install Slackware 10.2 and give it a try a full install.
Most likely if I am right it is set for the 2.4.x kernel. not sure keep me up to date.
It will not compile on any of my new systems.
the 2.4.X kernel is still maintained at kernel.org