eth_hdr to pico_eth_hdr reference fix, doc updates, picoTCP build for xcode

src/tap.hpp

@@ -44,12 +44,13 @@
 #include "Thread.hpp"
 #include "Phy.hpp"
 
-#include "netif/etharp.h"
+#if defined(SDK_LWIP)
+    #include "lwip.hpp"
+    #include "netif/etharp.h"
+#endif 
 
 #include "defs.h"
 #include "rpc.h"
-#include "lwip.hpp"
-// #include "jip.hpp"
 
 #if defined(SDK_PICOTCP)
     #include "picotcp.hpp"
@@ -172,6 +173,7 @@ namespace ZeroTier {
 
 		// lwIP
 		#if defined(SDK_LWIP)
+            netif interface, interface6;
 			lwIP_stack *lwipstack;
 		#endif
 		// jip
@@ -366,12 +368,7 @@ namespace ZeroTier {
 		void closeConnection(PhySocket *sock);
 
 		std::vector<Connection*> _Connections;
-
 		std::map<uint64_t, std::pair<PhySocket*, void*> > jobmap;
-		pid_t rpcCounter;
-
-		netif interface;
-		netif interface6;
 
 		Thread _thread;
 		std::string _dev; // path to Unix domain socket