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

tools/sdk/ssl/Makefile

@@ -11,7 +11,7 @@ install: all version-header
 
 bearssl/README.txt:
 	git submodule update --init --recursive bearssl
-	cd bearssl && git remote add bearssl https://www.bearssl.org/git/BearSSL
+	cd bearssl && (git remote add bearssl https://www.bearssl.org/git/BearSSL || true)
 
 merge-upstream:
 	cd bearssl && git pull bearssl master
@@ -20,3 +20,9 @@ version-header:
 	echo "// Do not edit -- Automatically generated by tools/sdk/ssl/bearssl/Makefile" > $(VER_H)
 	echo -n "#define BEARSSL_GIT " >> $(VER_H)
 	cd bearssl && git rev-parse --short HEAD >> ../$(VER_H)
+
+native: bearssl/README.txt
+	cd bearssl && make
+
+native32: bearssl/README.txt
+	cd bearssl && make CONF=Unix32