See https://build.syncthing.net/viewLog.html?buildId=32900&buildTypeId=SyncthingLite_Build. It’s necessary to make a config change to allow building Apps again (because Google updated the license of the Android SDK), but I don’t know where/ how the CI is configured.
I guess the build script should use some --accept-license or such. The sum total of CI-side setup is that it runs
./gradlew --no-daemon lint assembleDebug assembleRelease
in a livexp/android-sdk Docker image. There is not much to tweak there.
I think that the image contains accepting the licenses during the build time https://github.com/LiveXP/docker-android-sdk/blob/master/bin/docker-android-sdk-install. But the last image is a bit old https://hub.docker.com/r/livexp/android-sdk/tags. Is there a reason for using this special docker image? When searching in docker hub, the first (theoretically) matching image is https://hub.docker.com/r/runmymind/docker-android-sdk/tags which was updated 6 days ago.
I couldn’t guess, I have nothing to do with this repo. 
I’m sure there was a good reason at the time for whoever made the decision, and it appears to have worked since then until now. But experiment and see what works, if we need to adjust what image to use that’s a trivial change.
You need to accept the license post sdk installation which we do for the build image we construct for syncthing-fullfat.
Accepting the license after the installation (directly before calling gradle) did not work. However, using the image “runmymind/docker-android-sdk” did (even without adding the automatically agreeing to licenses). However, I can only change the config for the building on every commit and not for the release building, so I need someone who can change that.