Control: Change internal interfaces to batch-process input axis updates

These naturally come in bunches on many platforms like Android, so lay
some groundwork to also handle them in bunches to minimize locking in
the future.

Linux buildfix

Windows/XinputDevice.cpp

@@ -218,14 +218,17 @@ void XinputDevice::UpdatePad(int pad, const XINPUT_STATE &state, XINPUT_VIBRATIO
 	ApplyButtons(pad, state);
 	ApplyVibration(pad, vibration);
 
-	AxisInput axis;
-	axis.deviceId = (InputDeviceID)(DEVICE_ID_XINPUT_0 + pad);
+	AxisInput axis[6];
+	int axisCount = 0;
+	for (int i = 0; i < ARRAY_SIZE(axis); i++) {
+		axis[i].deviceId = (InputDeviceID)(DEVICE_ID_XINPUT_0 + pad);
+	}
 	auto sendAxis = [&](InputAxis axisId, float value, int axisIndex) {
 		if (value != prevAxisValue_[pad][axisIndex]) {
 			prevAxisValue_[pad][axisIndex] = value;
-			axis.axisId = axisId;
-			axis.value = value;
-			NativeAxis(axis);
+			axis[axisCount].axisId = axisId;
+			axis[axisCount].value = value;
+			axisCount++;
 		}
 	};
 
@@ -242,6 +245,10 @@ void XinputDevice::UpdatePad(int pad, const XINPUT_STATE &state, XINPUT_VIBRATIO
 		sendAxis(JOYSTICK_AXIS_RTRIGGER, (float)state.Gamepad.bRightTrigger / 255.0f, 5);
 	}
 
+	if (axisCount) {
+		NativeAxis(axis, axisCount);
+	}
+
 	prevState[pad] = state;
 	check_delay[pad] = 0;
 }