[PATCH] PR 17946: warning message for suspect "a && MASK"

[Thomas R. Truscott]

> > +         warning ("non-boolean constant in boolean context");
> 
> I think it's a bit difficult to infer from the warning that "&&" is
> the culprit.

I agree.  This is specific to TRUTH_ANDIF_EXPR, so the message could be:

    operand of && is a non-boolean constant