bad C in output_predicate_decls

[Robert Lipe]

Alexandre, your new code seems to use a GCC extension, thus breaking
bootstraps for systems where vendor cc isn't GNU C.  The '{}' below
isn't accepted by any ISO C compiler that I can find, though it is
accepted by GCC with -ansi. -pedantic warns about it.

static void
output_predicate_decls ()
{
#ifdef PREDICATE_CODES
  static struct {
    const char *name;
    RTX_CODE codes[NUM_RTX_CODE];
  } *p, predicate[] = {
    PREDICATE_CODES
    {NULL, {}}
  };