Migrate build to CMake and standard github workflows

Replace makefiles with CMakeLists.txt. This will allow for IDE and
platform agnostic builds of FFF.

Update the CI for FFF to use github workflows which don't depend on MS VC.
The workflow added will verify the pull requests sent to master buy
running 'buildandtest' which mirrors the developer workflow.

Signed-off-by: Yuval Peress <peress@google.com>

examples/weak_linking/include/bus.h

@@ -0,0 +1,6 @@
+#pragma once
+
+#include "error.h"
+
+bool bus_read_write( uint8_t dev, uint8_t registry, uint8_t* buffer, int len, bool assume_echo );
+bool bus_write( uint8_t dev, uint8_t registry, const uint8_t* buffer, int len, bool assume_echo );

examples/weak_linking/include/display.h

@@ -0,0 +1,5 @@
+#pragma once
+#include "error.h"
+
+bool display_init();
+void display_update( const char* info );

examples/weak_linking/include/error.h

@@ -0,0 +1,7 @@
+#pragma once
+
+#include <stdint.h>
+#include <stdbool.h>
+
+void runtime_error( const char* msg );
+char* runtime_error_nice_print( const char* msg );

examples/weak_linking/include/sensor.h

@@ -0,0 +1,6 @@
+#pragma once
+
+#include "error.h"
+
+bool sensor_init();
+float sensor_read();