make DRM_MODULES=radeon.o modules
make[1]: Entering directory `/usr/src/radeon-20060403-linux.i386/drm/linux-core'
make -C /lib/modules/2.6.21.1/source  SUBDIRS=`pwd` DRMSRCDIR=`pwd` modules
make[2]: Entering directory `/usr/src/linux-2.6.21.1'
  CC [M]  /usr/src/radeon-20060403-linux.i386/drm/linux-core/drm_auth.o
In file included from /usr/src/radeon-20060403-linux.i386/drm/linux-core/drm_auth.c:36:
/usr/src/radeon-20060403-linux.i386/drm/linux-core/drmP.h:44:26: error: linux/config.h: No such file or directory
make[3]: *** [/usr/src/radeon-20060403-linux.i386/drm/linux-core/drm_auth.o] Error 1
make[2]: *** [_module_/usr/src/radeon-20060403-linux.i386/drm/linux-core] Error 2
make[2]: Leaving directory `/usr/src/linux-2.6.21.1'
make[1]: *** [modules] Error 2
make[1]: Leaving directory `/usr/src/radeon-20060403-linux.i386/drm/linux-core'
make: *** [radeon.o] Error 2