proxy: guard if_indextoname bind block for Windows (_WIN32)

src/proxy/tcp_proxy_server.c

@@ -387,10 +387,13 @@ int tcp_proxy_server_handle_connect(struct UTUN_INSTANCE* inst, struct ll_entry*
         setsockopt(sock, SOL_SOCKET, SO_SETFIB, &g->tcp_proxy_server_fib, sizeof(g->tcp_proxy_server_fib));
     }
 #endif
+    // Bind to interface if specified (Linux only)
+#ifndef _WIN32
     if (g->tcp_proxy_server_netif_index > 0) {
         char ifname[IF_NAMESIZE];
         if (if_indextoname(g->tcp_proxy_server_netif_index, ifname)) socket_bind_to_device(sock, ifname);
     }
+#endif
 
     rc->tc = tcp_conn_create(inst->ua, sock, 1500, 8192, 4, 0, inst->config->global.tcp_recv_buf, on_fin_cb, on_error_cb, rc);
     if (!rc->tc) { DEBUG_ERROR(DEBUG_CATEGORY_PROXY, "TCP proxy server: tcp_conn_create failed"); socket_close_wrapper(sock); ctx->conn_count--; u_free(rc); queue_dgram_free(entry); queue_entry_free(entry); return -1; }