I try to build a new Kernel, everythink works fine on my system but im not able to make a new kernel. I read allready the Instruction here but always i do "make modules" i get following error :

agpgart_be.c: In function `agp_generic_create_gatt_table':
agpgart_be.c:591: warning: assignment from incompatible pointer type
agpgart_be.c: In function `amd_create_gatt_table':
agpgart_be.c:2476: warning: assignment from incompatible pointer type
agpgart_be.c:2477: warning: assignment from incompatible pointer type
agpgart_be.c: In function `amd_free_gatt_table':
agpgart_be.c:2503: warning: assignment from incompatible pointer type
agpgart_be.c:2504: warning: assignment from incompatible pointer type
agpgart_be.c: In function `serverworks_create_gatt_table':
agpgart_be.c:3587: warning: assignment from incompatible pointer type
agpgart_be.c:3588: warning: assignment from incompatible pointer type
agpgart_be.c: In function `serverworks_free_gatt_table':
agpgart_be.c:3616: warning: assignment from incompatible pointer type
agpgart_be.c:3617: warning: assignment from incompatible pointer type
ld -m elf_i386 -r -o agpgart.o agpgart_fe.o agpgart_be.o
make[3]: Leaving directory `/usr/src/kernel-source-2.4.20-xfs/drivers/char/agp'
make -C drm modules
make[3]: Entering directory `/usr/src/kernel-source-2.4.20-xfs/drivers/char/drm'
gcc-2.95 -D__KERNEL__ -I/usr/src/kernel-source-2.4.20-xfs/include -Wall -Wstrict-prototypes -Wno-trigraphs -O2 -fno-strict-aliasing -fno-common -fomit-frame-pointer -pipe -mpreferred-stack-boundary=2 -march=i686 -DMODULE -nostdinc -iwithprefix include -DKBUILD_BASENAME=tdfx_drv -c -o tdfx_drv.o tdfx_drv.c
In file included from tdfx_drv.c:35:
drmP.h:932: redefinition of `__cmpxchg'
/usr/src/kernel-source-2.4.20-xfs/include/asm/system.h:244: `__cmpxchg' previously defined here
make[3]: *** [tdfx_drv.o] Fehler 1
make[3]: Leaving directory `/usr/src/kernel-source-2.4.20-xfs/drivers/char/drm'
make[2]: *** [_modsubdir_drm] Fehler 2
make[2]: Leaving directory `/usr/src/kernel-source-2.4.20-xfs/drivers/char'
make[1]: *** [_modsubdir_char] Fehler 2
make[1]: Leaving directory `/usr/src/kernel-source-2.4.20-xfs/drivers'
make: *** [_mod_drivers] Fehler 2

I allready updated the System and changed the DRI drivers, so i dont want to reinstall to try if it works on a fresh install.

please help