diff --git a/mach/vax4/libbsd4_2/compmodule b/mach/vax4/libbsd4_2/compmodule
new file mode 100755
index 000000000..3b054dea9
--- /dev/null
+++ b/mach/vax4/libbsd4_2/compmodule
@@ -0,0 +1,4 @@
+if vax4 -O -c -L -I../../../h -I. $1 1>&2
+then echo `basename $1 $2`.o
+else exit 1
+fi