Move IPV4_LOCALHOST to net.h

This constant will be used from several files.

app/src/server.c

@@ -161,7 +161,6 @@ disable_tunnel(struct server *server) {
 
 static bool
 listen_on_port(struct sc_intr *intr, sc_socket socket, uint16_t port) {
-#define IPV4_LOCALHOST 0x7F000001
     return net_listen_intr(intr, socket, IPV4_LOCALHOST, port, 1);
 }
 

app/src/util/net.h

@@ -22,8 +22,11 @@
 # include <sys/socket.h>
 # define SC_INVALID_SOCKET -1
   typedef int sc_socket;
+
 #endif
 
+#define IPV4_LOCALHOST 0x7F000001
+
 bool
 net_init(void);