diff --git a/mach/mantra/int/prep b/mach/mantra/int/prep
index 04e076d2e..4f4c41996 100755
--- a/mach/mantra/int/prep
+++ b/mach/mantra/int/prep
@@ -1,3 +1,3 @@
-rm temp.c
+rm -f temp.c
 cat header deffile $1 >> temp.c
-cpp -P temp.c >$2
+../../../lib/cpp -P temp.c >$2