h8300 16-bit warnings

[Joel Sherrill]

Hi,

I am going on a pre-branching warning hunt and Ralf suggested
going over the h8300-multilib set of warnings.  I am collecting
notes on what I can see a fix for but don't precisely know the
right answer.  Many are very simple due to printf format specifications
or not using the correct and already existing type.

+ sys/ioccomm.h 16-bit clean _IOxx definitions

+ what type should you use when casting a pointer to an
  integer?

+ sys/mbuf.h M_COPYALL needs to have a 16-bit clean definition.

Any thoughts on the above?

I need to doublecheck what I have done before I comment what I have.
I don't want to accidentally make it worse. :)

--joel