I got too myself some boards. XI is indeed a 382 clone, but it seems that the XI core library is missing yield() functionality.
I managed to compile my mysensors sketch with first forcing the #define ARDUINO_ARCH_AVR in the sketch and
with some modifications at the XI core library:

• I added the void yield(void); somewhere in ..\ARDUINO\hardware\wemos\XI\cores\lgt8f\Arduino.h
  
• I added the hooks.c file to ..\ARDUINO\hardware\wemos\XI\cores\lgt8f\ from https://github.com/arduino/Arduino/blob/master/hardware/arduino/avr/cores/arduino/hooks.c

However i did not yet upload the sketch to the board, I'll later when I get home.

hi, had the same problem. Replace the strcmp_P function with strcmp in MyGatewayTransportMQTTClient.cpp, line 74.

			// Topic prefix
			
			if (strcmp(str, MY_MQTT_SUBSCRIBE_TOPIC_PREFIX) != 0) {					
				return;
			}
			break;
		}

I think that topic comparison could be skipped...