abandon K&R C ?(was: Re: isearch multiple buffers)

[Dan Nicolaescu]

Richard Stallman <address@hidden> writes:

  >     X10  (window-system-version mentions it, is it still supported?)
  > 
  > I think all code specific to X10 was all deleted ages ago.
  > There are a few conditionals that test HAVE_X11, but they really
  > use it to test whether X is present at all.
  > 
  > There are still conditionals for X11R3 (testing HAVE_X11R4).  That
  > must be long obsolete.  We can delete them if that would save us any
  > trouble.

This also seems be a good opportunity abandon K&R C. Functions that
use the ISO C style are sprinkled all over the place, so it's doubtful
that emacs would build now with a K&R only compiler.
AFAIK binutils, gdb and gcc did this a few years ago with no
problems.
(We should probably wait for the unicode-2 branch to be merged first to
 avoid unnecessary merge conflicts).