* eval.c (evaluate_subexp_standard): Report error when attempting to
evaluate subscripts for types which cannot be subscripted.
* valarith.c (value_x_binop, value_x_unop): Add noside parameter.
Return a zero value with the return type of the member function
if noside is EVAL_AVOID_SIDE_EFFECTS instead of calling the member
function.
* values.h (value_x_binop, value_x_unop): Update prototypes
accordingly.
* eval.c (evaluate_subexp_standard): Update all callers of
value_x_binop, value_x_unop accordingly.
* valarith.c (value_neg, value_complement): Perform ANSI C/C++
integral promotion on operands.