Mark buffered receive data as volatile

All three of these members can be updated in 'receive()' which is now typically called via a USB interrupt rather than in the user's program flow.

Author: dmadison

src/XInput.cpp

@@ -460,7 +460,7 @@ void XInputGamepad::reset() {
 
 	// Reset received data (rx)
 	player = 0;  // Not connected, no player
-	memset(rumble, 0x00, sizeof(rumble));  // Clear rumble values
+	memset((void*) rumble, 0x00, sizeof(rumble));  // Clear rumble values
 	ledPattern = XInputLEDPattern::Off;  // No LEDs on
 
 	// Reset rescale ranges

src/XInput.h

@@ -136,9 +136,9 @@ class XInputGamepad {
 	boolean newData;  // Flag for tx data changed
 
 	// Received Data
-	uint8_t player;  // Gamepad player #, buffered
-	uint8_t rumble[2];  // Rumble motor data in, buffered
-	XInputLEDPattern ledPattern;  // LED pattern data in, buffered
+	volatile uint8_t player;  // Gamepad player #, buffered
+	volatile uint8_t rumble[2];  // Rumble motor data in, buffered
+	volatile XInputLEDPattern ledPattern;  // LED pattern data in, buffered
 	RecvCallbackType recvCallback;  // User-set callback for received data
 
 	void parseLED(uint8_t leds);  // Parse LED data and set pattern/player data