natural constraint is only valid in the root of enumeration

git-svn-id: https://asn1c.svn.sourceforge.net/svnroot/asn1c/trunk@1385 59561ff5-6e30-0410-9f3c-9617f08c8826
diff --git a/skeletons/NativeEnumerated.c b/skeletons/NativeEnumerated.c
index 12b079e..b6b47e1 100644
--- a/skeletons/NativeEnumerated.c
+++ b/skeletons/NativeEnumerated.c
@@ -179,7 +179,7 @@
 	if(ct->flags & APC_EXTENSIBLE) {
 		if(per_put_few_bits(po, inext, 1))
 			_ASN_ENCODE_FAILED;
-		ct = 0;
+		if(inext) ct = 0;
 	} else if(inext) {
 		_ASN_ENCODE_FAILED;
 	}