@djoni_w what you can do (as it should work) :

get Linux (but it should work in WSL if you have an up-to-date windows with the 16.04 Ubuntu) follow https://github.com/recalbox/recalbox-os/wiki/Compilation-%26-Modifications-(EN) and stop once you've typed make recalbox-${arch}_defconfig now type make gamecon-gpio-rpi-patch now cd output/build/gamecon-gpio-rpi (there might be some more following the folder name, check by yourself) edit the source code to change the delay to 5 climb back in the folder where you issued the make commands (cd -should do it if you haven't changed directory since the last cd) now make gamecon-gpio-rpi watch the output, the .ko file should appear. If you can't find it, it should be at least in the folder where you edited the source code

If you're having trouble with all that, i'll compile one for you.

For the explanation : a ko is a kernel object. In this case it's a driver that runs in the kernel space (as opposed to user space)