New function to compute the CAR and signal an error if a non-LIST is given.
New function to compute the CAR and signal an error if a non-LIST is given.

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