Use LET for single store variables so that we don't need M-V-B early.
Use LET for single store variables so that we don't need M-V-B early.

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