Paho MQTT API linker errors in Arduino Create

[agnathan]

A bug that was recently introduced in the Arduino Create backend. Our MQTT sketch compiled until recently. Now the Paho MQTT async apis are undefined.

Here’s the lab
https://create.arduino.cc/editor/danielholmlund/11194965-2c77-4d59-9849-8a79423c047f/preview

I've attached the output from the compiler.

arduino-mqtt-build-output.txt

[facchinm]

Hi @agnathan , this was due to a mismatch between the builder and the mraa core; it should be solved by today, thanks

[agnathan]

Excellent! Thanks, the workshop in Milan next week and the upcoming Brazil workshop are using MQTT and it's great to have this working.