bug fix for c-torture test execute/bf-sign-2.c

[Jeffrey A Law]

  In message < 199710221354.OAA31493@phal.cygnus.co.uk >you write:
  > execute/bf-sign-2.c currently fails for targets with 16 bit ints.
  > Here is a fix:
  > 
  > Wed Oct 22 14:08:50 1997 J"orn Rennecke <amylaar@cygnus.co.uk>
  > 
  > 	* execute/bf-sign-2.c (struct X): New member u15.
  > 	(main): Check u15.  Check for u31 depends on size of int.
I don't remember this failing for the mn10200, which is a 16bit int
target.  Maybe you should describe why it's failing on yours so that
we can understand your patch.

jeff