Boot the Fedora167 virtual computer (enable PAE to be able to boot).
Login: root/OperacniSystemy
cd /root/rpmbuild/BUILD/kernel-2.6.3/linux-2.6.31.i686/
look at files:
less arch/x86/include/asm/unistd_32.h
less arch/x86/kernel/syscall_table_32.S

modify the functions sys_pb167_fce1 and sys_pb167_fce2 in ipc/sem.c
e.g. replace "return 0;" with "return 8;"

compile kernel:
make
make modules
make modules_install

configure kernel:
cp arch/x86/boot/bzImage /boot
edit /etc/grub.conf file - add one entry (change the title and kernel path
to /bzImage)

reboot and select the new kernel

test the new system call with a simple C code:

#include <linux/unistd.h>
#include <stdio.h>

int main(void)
{
int y=syscall(337);
int x=syscall(338,4,3);
printf("const: %i, 4 + 3 = %i\n",y,x);
}