Compiling the tests with -Wextra results to lots of warnings for unused
parameters. Annotate these cases with the `unused' attribute to avoid
the warnings.
(resume): Likewise.
(nop): Remove.
(main): Don't cast function pointer to different prototypes. That's apparently
not allowed. icc v8.0 complains about it and GCC 3.5 will actually
generate crashing code when this is done. Talk about terminated with
extreme prejudice!
(Logical change 1.213)
