#ifdef ALLOW_DEPTH_CONTROL
# if ((defined ALLOW_DEPTH_CONTROL) (defined NONLIN_FRSURF))
# if ((defined NONLIN_FRSURF) (defined ALLOW_DEPTH_CONTROL)) (defined ALLOW_GMREDI)
# if (defined NONLIN_FRSURF) (defined ALLOW_DEPTH_CONTROL)
# ifdef ALLOW_DEPTH_CONTROL
defined (ALLOW_DEPTH_CONTROL))