build: prepend "NFD_" to various macro names to avoid conflicts

Change-Id: Icc370968e3d38fef80ece35a2aed56450f54b653
diff --git a/daemon/face/pcap-helper.hpp b/daemon/face/pcap-helper.hpp
index 5d239ce..1f08d85 100644
--- a/daemon/face/pcap-helper.hpp
+++ b/daemon/face/pcap-helper.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2014-2017,  Regents of the University of California,
+/*
+ * Copyright (c) 2014-2021,  Regents of the University of California,
  *                           Arizona Board of Regents,
  *                           Colorado State University,
  *                           University Pierre & Marie Curie, Sorbonne University,
@@ -28,7 +28,7 @@
 
 #include "core/common.hpp"
 
-#ifndef HAVE_LIBPCAP
+#ifndef NFD_HAVE_LIBPCAP
 #error "Cannot include this file when libpcap is not available"
 #endif