more lwIP physical interfaces (#6680)

This commit adds W5500 W5100 and ENC28j60 drivers from @njh with credits
They are available in libraries/
An example is added in W5500 examples directory

plus:
* Extract dhcp server from lwip2 and add it to the core as a class.
  It must always be present, it is linked and can be called by fw on boot.
  So it cannot be stored in a library.
* ethernet: static or dhcp works
* PPPServer: example
* bring WiFi.config() to the lwIP generic interface (argument reorder common function)
* move hostname() from WiFI-STA to generic interface
* remove non readable characters from dhcp-server comments
* dhcp-server: magic_cookie is part of bootp rfc
* fixes from https://github.com/d-a-v/W5500lwIP/issues/17
* enable lwip_hook_dhcp_parse_option()
* +ethernet tcp client example in w5500 library examples

tests/host/Makefile

@@ -299,6 +299,7 @@ ARDUINO_LIBS := \
 		IPAddress.cpp \
 		Updater.cpp \
 		base64.cpp \
+		LwipIntf.cpp \
 		LwipIntfCB.cpp \
 	) \
 	$(addprefix $(abspath ../../libraries/ESP8266WiFi/src)/,\

tests/host/common/user_interface.cpp

@@ -41,6 +41,49 @@
 
 #include "MocklwIP.h"
 
+#include <LwipDhcpServer.h>
+
+bool DhcpServer::set_dhcps_lease(struct dhcps_lease *please)
+{
+    (void)please;
+    return false;
+}
+
+bool DhcpServer::set_dhcps_lease_time(uint32 minute)
+{
+    (void)minute;
+    return false;
+}
+
+bool DhcpServer::set_dhcps_offer_option(uint8 level, void* optarg)
+{
+    (void)level;
+    (void)optarg;
+    return false;
+}
+
+void DhcpServer::end ()
+{
+}
+
+bool DhcpServer::begin (struct ip_info *info)
+{
+    (void)info;
+    return false;
+}
+
+DhcpServer::DhcpServer (netif* netif)
+{
+    (void)netif;
+}
+
+DhcpServer::~DhcpServer ()
+{
+    end();
+}
+
+DhcpServer dhcpSoftAP(nullptr);
+
 extern "C"
 {
 

tests/restyle.sh

@@ -13,6 +13,8 @@ test -d libraries
 all="
 libraries/ESP8266mDNS
 libraries/Wire
+libraries/lwIP*
+cores/esp8266/Lwip*
 cores/esp8266/core_esp8266_si2c.cpp
 libraries/Netdump
 "