Correct internal prototype of __builtin_saveregs

[Jeffrey A Law]

  In message < 20000802100815.D29910@wolery.cumb.org >you write:
  > When compiling libgcc on targets that don't need a specialized
  > __builtin_saveregs, we get a warning about no previous prototype for
  > the function, despite the fact that it's prototyped in libgcc2.h. This
  > is because the internal declaration has no prototype.
  > 
  > This patch changes c_common_nodes_and_builtins such that __builtin_saveregs
  > is given a (void) prototype.  __builtin_apply_args and __builtin_next_arg
  > keep their unspecified prototype.
  > 
  > [Are these routines still used?  They appear to be only for the old
  > varargs implementation.]
  > 
  > Bootstrapped i386-linux.  OK to commit?
  > 
  > zw
  > 
  > 	* c-common.c (c_common_nodes_and_builtins): Add ptr_ftype_any
  > 	function type.  Change ptr_ftype to be void * (void).  Give
  > 	__builtin_next_arg and __builtin_apply_args ptr_ftype_any.
I don't think those routines are used anymore.  I'd rather remove them if
they're no longer supported.

jeff