fix gcc compile error (cannot call foo(&v) with v)

libwccl/ops/matchrule.cpp

@@ -17,7 +17,9 @@ void MatchRule::apply(const boost::shared_ptr<Corpus2::AnnotatedSentence>& s)
 	if (!apply_) {
 		return; // no-op (default) version
 	}
-	apply_->execute(ActionExecContext(SentenceContext(s), variables_));
+	SentenceContext sc(s);
+	ActionExecContext aec(sc, variables_);
+	apply_->execute(aec);
 }
 
 std::string MatchRule::to_string(const Corpus2::Tagset &tagset) const