UF_CCS was used in compiler/main/Constants.lhs
/* ----------------------------------------------------------------------------
- * $Id: Constants.h,v 1.15 2001/07/31 13:44:37 simonmar Exp $
+ * $Id: Constants.h,v 1.16 2001/07/31 18:30:22 qrczak Exp $
*
* (c) The GHC Team, 1998-1999
*
#define UF_RET 0
#define UF_SU 1
#define UF_UPDATEE 2
+#define UF_CCS 3
/* -----------------------------------------------------------------------------
SEQ frame size