The configure script completed successfully, but when running make, the following error occurs:

make[2]: Entering directory `/root/src/xorg/xf86-video-ati-6.14.4/src'
  CC     ati.lo
  CC     atimodule.lo
  CCLD   ati_drv.la
  CC     radeon_accel.lo
In file included from radeon.h:76,
                 from radeon_accel.c:80:
/usr/include/GL/glxint.h:36:19: error: GL/gl.h: No such file or directory
In file included from radeon.h:76,
                 from radeon_accel.c:80:
/usr/include/GL/glxint.h:103: error: expected specifier-qualifier-list before ‘GLboolean’
make[2]: *** [radeon_accel.lo] Error 1
make[2]: Leaving directory `/root/src/xorg/xf86-video-ati-6.14.4/src'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/root/src/xorg/xf86-video-ati-6.14.4'
make: *** [all] Error 2

Installing libgl1-mesa-dev on Debian 6.0.3 allows the build to complete successfully. I guess the configure script should check for gl.