diff --git a/Make/makedefs b/Make/makedefs
index 4eafb63f5..ac26a0629 100644
--- a/Make/makedefs
+++ b/Make/makedefs
@@ -164,7 +164,7 @@ ifeq ($(OS),IRIX)
 	 	       -DEBUG:woff=1682 -DEBUG:woff=3303\
 		       -MDupdate $(MAKEDEPEND)
   OPTF              = -O2 
-  DBGF              = -g -DOSG_COMPILE_UNIT_TESTS
+  DBGF              = -g -DOSG_COMPILE_UNIT_TESTS  -DOSG_USE_MEMORY_MANAGER
   SHARED            = -shared
   ARCH              = 32
 ifeq ($(ARCH),64)