[V3 PATCH] char extraction uses wrong cast

[Jason Merrill]

>>>>> "Phil" == Phil Edwards <pedwards@disaster.jaj.com> writes:

> As discussed on the V3 list, the code for "is >> c" where c was specified
> as a signed or signed char was wrong 
> (static_cast's don't yield lvalues).
                ^to non-reference types

Jason