* Add cast to hardclock when it's used directly as an interrupt handler.
* Add a null-interrupt-establish function, to avoid int vs void lint
in pica/dev/dma.c.
* fix include in pica/include/pccons.h to work with "standard"
kernel-compile include path.
- split softc size and match/attach out from cfdriver into
a new struct cfattach.
- new "attach" directive for files.*. May specify the name of
the cfattach structure, so that devices may be easily attached
to parents with different autoconfiguration semantics.
