Added method on ACCUMULATION-VARIABLES specialized to RETURN-CLAUSE.
Added method on ACCUMULATION-VARIABLES specialized to RETURN-CLAUSE.

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