Add RPi4 detection

gpio/readall.c

@@ -307,6 +307,8 @@ static void plus2header (int model)
     printf (" +-----+-----+---------+------+---+---Pi 3---+---+------+---------+-----+-----+\n") ;
   else if (model == PI_MODEL_3P)
     printf (" +-----+-----+---------+------+---+---Pi 3+--+---+------+---------+-----+-----+\n") ;
+  else if (model == PI_MODEL_4)
+    printf (" +-----+-----+---------+------+---+---Pi 4+--+---+------+---------+-----+-----+\n") ;
   else
     printf (" +-----+-----+---------+------+---+---Pi ?---+---+------+---------+-----+-----+\n") ;
 }
@@ -353,7 +355,8 @@ void doReadall (void)
   else if ((model == PI_MODEL_BP) || (model == PI_MODEL_AP) ||
 	(model == PI_MODEL_2) ||
 	(model == PI_MODEL_3) || (model == PI_MODEL_3P) ||
-	(model == PI_MODEL_ZERO) || (model == PI_MODEL_ZERO_W))
+	(model == PI_MODEL_ZERO) || (model == PI_MODEL_ZERO_W) ||
+	(model == PI_MODEL_4))
     piPlusReadall (model) ;
   else if ((model == PI_MODEL_CM) || (model == PI_MODEL_CM3))
     allReadall () ;

wiringPi/wiringPi.h

@@ -100,6 +100,7 @@
 #define	PI_MODEL_CM3		10
 #define	PI_MODEL_ZERO_W		12
 #define	PI_MODEL_3P 		13
+#define	PI_MODEL_4 		17
 
 #define	PI_VERSION_1		0
 #define	PI_VERSION_1_1		1