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

tests/host/common/MockSPI.cpp

@@ -0,0 +1,63 @@
+/*
+ Arduino emulation - spi
+ Copyright (c) 2018 david gauchard. All rights reserved.
+
+ Permission is hereby granted, free of charge, to any person obtaining a
+ copy of this software and associated documentation files (the "Software"),
+ to deal with the Software without restriction, including without limitation
+ the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ and/or sell copies of the Software, and to permit persons to whom the
+ Software is furnished to do so, subject to the following conditions:
+
+ - Redistributions of source code must retain the above copyright notice,
+   this list of conditions and the following disclaimers.
+
+ - Redistributions in binary form must reproduce the above copyright notice,
+   this list of conditions and the following disclaimers in the
+   documentation and/or other materials provided with the distribution.
+
+ - The names of its contributors may not be used to endorse or promote
+   products derived from this Software without specific prior written
+   permission.
+
+ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ THE CONTRIBUTORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
+ OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ DEALINGS WITH THE SOFTWARE.
+*/
+
+#include <SPI.h>
+
+#if !defined(NO_GLOBAL_INSTANCES) && !defined(NO_GLOBAL_SPI)
+SPIClass SPI;
+#endif
+
+SPIClass::SPIClass ()
+{
+}
+
+uint8_t SPIClass::transfer(uint8_t data)
+{
+	return data;
+}
+
+void SPIClass::begin()
+{
+}
+
+void SPIClass::end()
+{
+}
+
+void SPIClass::setFrequency(uint32_t freq)
+{
+	(void)freq;
+}
+
+void SPIClass::setHwCs(bool use)
+{
+	(void)use;
+}