rem: visible (unsigned int ch)
add: visible (cc_t ch)
context: visible (unsigned int ch){  static char buf[10];  char *bpout = buf;  if (ch == _POSIX_VDISABLE)    return "<undef>";  if (ch >= 32)    {      if (ch < 127)	*bpout++ = ch;      else if (ch == 127)	{	  *bpout++ = '^';	  *bpout++ = '?';	}      else	{	  *bpout++ = 'M',	    *bpout++ = '-';	  if (ch >= 128 + 32)	    {	      if (ch < 128 + 127)		*bpout++ = ch - 128;	      else		{		  *bpout++ = '^';		  *bpout++ = '?';		}	    }	  else	    {	      *bpout++ = '^';	      *bpout++ = ch - 128 + 64;	    }	}    }  else    {      *bpout++ = '^';      *bpout++ = ch + 64;    }  *bpout = '\0';  return (const char *) buf;}