diff --git a/examples/sample.makefile.regen b/examples/sample.makefile.regen
index 04b5608..57a5350 100755
--- a/examples/sample.makefile.regen
+++ b/examples/sample.makefile.regen
@@ -28,7 +28,7 @@
 fi
 
 FIXEDPDU=`echo "[$ASN1PDU]" | sed -e "s/.*-pdu=auto.*//"`
-if test "$FIXEDPDU" ; then
+if test ! "$FIXEDPDU" ; then
 	EXTRA_CFLAGS="$EXTRA_CFLAGS -DASN_PDU_COLLECTION"
 fi