Fix map() division by zero (#2848)

cores/esp32/WMath.cpp

@@ -65,9 +65,12 @@ long random(long howsmall, long howbig)
     return random(diff) + howsmall;
 }
 
-long map(long x, long in_min, long in_max, long out_min, long out_max)
-{
-    return (x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min;
+long map(long x, long in_min, long in_max, long out_min, long out_max) {
+    long divisor = (in_max - in_min);
+    if(divisor == 0){
+        return -1; //AVR returns -1, SAM returns 0
+    }
+    return (x - in_min) * (out_max - out_min) / divisor + out_min;
 }
 
 unsigned int makeWord(unsigned int w)