If you try to compile zaptel on FC6 then you’ll get an error
config.h file is no longer used by the kernel so we have to make some modification in order to compile zaptel driver.
First solution is remove from the source of zaptel all inclusions of config.h (in zconfig.h, zaptel.h and torisa.c).
Second is to make in /usr/src/kernels/2.6.18-1.2798.fc6-i686/include/linux/ file config.h which contains this code
/* This file is no longer in use and kept only for backward compatibility.
- autoconf.h is now included via -imacros on the commandline
#if !defined (KERNEL) && !defined(KERNGLUE)
#error including kernel header in userspace; use the glibc headers instead!
This solution was found here phoronix.com/redblog/?p=blog&i=NTUwMA after googling some time.
Maybe this will help anyone not to waste their time on this as I did.