7.4: Fixed STRING->SYMBOL expansion to test that it's argument is a

7.4: Fixed STRING->SYMBOL expansion to test that it's argument is a
constant whose value is a string rather than applying STRING?
directly (which has been broken since it was added in 1992.)  Fixed
INTERN likewise.

8.0: treat INTERN similarly to STRING->SYMBOL: Add INTERN as a
integrated to a global reference.  Added type rule and constant
folding rule for intern. (This is better than constant folding at
integration time since it deals with constant propagation.)