GPU support for drone-runner-docker

I am looking for the ability to run builds in docker containers with access to GPU. When starting the runner with --gpus all flag, the docker image created by the runner does not appear to have access to a GPU. Does anyone know how to enable this? New to Go, so digging through the source code is taking me a while. Thanks!

Edit: Runtime seems to be HostConfig parameter, just not clear to me how to set it.