--- Yap-5.0.1.orig/C/exec.c	2005-10-18 04:21:54.000000000 +1300
+++ Yap-5.0.1/C/exec.c	2006-02-23 22:32:20.000000000 +1300
@@ -1362,7 +1362,7 @@
   READ_LOCK(ppe->PRWLock);
   CodeAdr = ppe->CodeOfPred;
   READ_UNLOCK(ppe->PRWLock);
-#if !USE_MALLOC
+#if !USE_SYSTEM_MALLOC
   if (Yap_TrailTop - HeapTop < 2048) {
     Yap_PrologMode = BootMode;
     Yap_Error(OUT_OF_TRAIL_ERROR,TermNil,