org.xcsoar hosts its own git repo. Self-hosted git repos can be flaky, and
they are blocked by the Guardian Project jenkins server, so use an app from
github.com instead.
on the GP jenkins, I got this:
+ git pull
From https://gitlab.com/fdroid/fdroiddata
1df2d03..621ef4f master -> origin/master
You are not currently on a branch. Please specify which
branch you want to merge with. See git-pull(1) for details.
git pull <remote> <branch>
Also, when cloning, no need to specify the branch and only download that
one. We already have only a single branch. And forcing master isn't
necessary.
