Sketch emulation on host (#5342)

* WIP compile examples on host with 'make examples'

* WIP bufferize tcp input

* WIP Makefile

* WIP network to rework, tcp/udp to factorize, udp addresses broken

* minor changes to the core

* WIP basic udp working

* WIP mdns

* WIP mcast receiving, not sending

* WIP mdns OK

* beta version

* SSL + doc

* update travis host test command

* licenses

* typo

* doc: arduino builder is not around: declare functions before calling them

* fix with latest SSL PR, compile in 32 bits mode

* fix make clean

* make -m32 optional

* 32bits compiler ability tester

* WIP

* WIP (fix 1 vtable error, still another one to hunt with using spiffs)

* example astyle

* fix os_printf_plus

* load / save mock spiffs

* fix style

* fix using spiffs/mock

* don't mess ram

* update doc

* remove leftover

* optimization -Os except for CI, rename ARCH32 to FORCE32

* revert useless cast (not even compiled)

* remove unused function

* use proper type for pointer arithmetics

* makefile: sketch object and cpp file moved to bin/ directories
easier to clean, and IDE don't like them

* changes for review

* make use of %zd

* less verbose makefile by default (option)

* update readme

cores/esp8266/Esp.cpp

@@ -22,7 +22,7 @@
 #include "flash_utils.h"
 #include "eboot_command.h"
 #include <memory>
-#include "interrupts.h"
+#include <interrupts.h>
 #include "MD5Builder.h"
 #include "umm_malloc/umm_malloc.h"
 #include "cont.h"
@@ -165,6 +165,7 @@ void EspClass::restart(void)
 uint16_t EspClass::getVcc(void)
 {
     InterruptLock lock;
+    (void)lock;
     return system_get_vdd33();
 }