Cross compile toolchain for OS?

Is there a toolchain or something for cross-compiling things into the OS? I have been asking lots of dumb questions and this is just the next one in the list.

I have finally got to the point where I can see all the information I want from a couple of mosquito_sub commands. Now I need to create an app/script to make use of it. There is no paho.mqtt on the device, nor gcc/g++, so it looks like I have to do something on my host machine and then move the app over (since I want this to run on the gateway which is a Pi Zero W).

I searched the forums and the github page, but could find to answers for this type of question. If I am yet again looking at this the wrong way, I am happy to try other options.

OK, I am attempting to build the docker image and include in gcc and pip3. It //builds// fine, but I have two questions.

1 - It seems to build the “base” image, how do I build the “full” one? <<<==== I think I see the answer to this, I just need to run “bitbake chirpstack-gateway-os-full” instead of "bitbake chirpstack-gateway-os-base"*
2 - What do I do about the software updates file usually supplied? Are those updates basically baked into this image? Or do I need to still run that over top of it once I install onto an SD card?