Used new function ENSURE-BUILT-IN-CLASS rather than ENSURE-CLASS.
Used new function ENSURE-BUILT-IN-CLASS rather than ENSURE-CLASS.

vtomole/SICL,clasp-developers/SICL,clasp-developers/SICL,vtomole/SICL,clasp-developers/SICL,vtomole/SICL,clasp-developers/SICL,vtomole/SICL