diff --git a/scripts/Mmake.rules b/scripts/Mmake.rules
index 082cfeca3..fbd1b0b90 100644
--- a/scripts/Mmake.rules
+++ b/scripts/Mmake.rules
@@ -1,5 +1,5 @@
 #-----------------------------------------------------------------------------#
-# Copyright (C) 1995-1998 The University of Melbourne.
+# Copyright (C) 1995-1999 The University of Melbourne.
 # This file may only be copied under the terms of the GNU General
 # Public License - see the file COPYING in the Mercury distribution.
 #-----------------------------------------------------------------------------#
@@ -34,7 +34,7 @@ ifeq ($(MMAKE_USE_SUBDIRS),yes)
 MCFLAGS += --use-subdirs
 MSCFLAGS += --use-subdirs
 MNCFLAGS += --use-subdirs
-MGNUCFLAGS += -I.
+ALL_MGNUCFLAGS += -I.
 
 endif