We’ve seen more QEMU gotchas on with golang projects, but it’s always good to have some feedback on other serious compilations, what kind of issues you run into.
By the way 
, just tried it out, it seems you can use a resin.io device running a -dev resinOS version in local mode to be your builder:
resin deploy --build --source . --dockerHost <shortUUID>.local --dockerPort 2375 AppName
(where the <shortUUID> is what’s displayed in the dashboard, and the AppName is the app that you are building). I think the device should be the same architecture as the one you are compiling for (e.g. you can have one RPi3 to compile for all your RPi3 apps), but otherwise, here’s a no-extra-setup unvirtualized builder. 
(though probably not very speedy).