tag/TagBuilder: overload Commit() returning a Tag object

src/tag/TagBuilder.cxx

@@ -133,6 +133,14 @@ TagBuilder::Commit(Tag &tag)
 	Clear();
 }
 
+Tag
+TagBuilder::Commit()
+{
+	Tag tag;
+	Commit(tag);
+	return tag;
+}
+
 Tag *
 TagBuilder::CommitNew()
 {

src/tag/TagBuilder.hxx

@@ -96,6 +96,12 @@ public:
 	 */
 	void Commit(Tag &tag);
 
+	/**
+	 * Create a new #Tag instance from data in this object.  This
+	 * object is empty afterwards.
+	 */
+	Tag Commit();
+
 	/**
 	 * Create a new #Tag instance from data in this object.  The
 	 * returned object is owned by the caller.  This object is