Prototyping files like i386.h

[Jeffrey A Law]

  In message < Pine.SOL.3.90.980218113427.12315J-100000@bond.informatik.rwth-aachen.de >you write:
  > Currently, the function declarations in files like i386.h can't be
  > prototyped properly, because they get included before rtl.h and tree.h. 
  > This patch is an attempt to solve the problem. (Obviously, a lot of work
  > is still necessary to do the same thing for the other ports.)
Let's hold off on trying to prototype this stuff for now.  I'd like
to deal with the non-controversial prototype first.  Then return
to the issue of how to deal with the rtl.h/tree.h issues.

jeff