Add Stringification macro

Signed-off-by: Frederic.Pillon <frederic.pillon@st.com>

Author: fpistm

cores/arduino/utils.h

@@ -27,4 +27,8 @@
 // Concatenate 2 strings separated by space
 #define CONCATS(s1, s2) (s1" " s2)
 
+// Stringification
+#define xstr(s) str(s)
+#define str(s) #s
+
 #endif

cores/arduino/wiring.h

@@ -28,6 +28,7 @@
 
 #include "binary.h"
 #include "itoa.h"
+#include "utils.h"
 
 #include "wiring_analog.h"
 #include "wiring_constants.h"