If I manually run some steps of the process, not all of the normal cruft
might be left behind. I'm not really sure which of the multiple copies of
the images are actually required, but these both seem to work when present.
When running `fdroid build --all` on a buildserver with thousands of apps,
it was frequently hitting the open file limit. This increases the open
file limit based on how many apps are being process. It is doubled to
provide a margin of safety.
There are probably open file leaks which ideally would be fixed, but this
is also useful to make things more resilient to all the random stuff apps
include in their build systems.
If a git fetch/clone/submodule URL points to gitlab, github, bitbucket, etc
and that repo does not exist any more, those services will prompt the user
for a username/password so that the service can check if its a private
repo. Private repos show up the same as non-existent repos. This employs
two techniques for making sure that git never waits at those prompts. It
instead should just fail immediately. The buildserver has been hanging on
these prompts forever, until manually killed. This change will apply to
updates both on the buildserver host, and the buildserver guest vm.
This uses the "insteadOf" git config option to rewrite URLs to always use
HTTPS and then include a fake username/password so that git will use those
in the prompts and fail immediately. This trick has been in use on the
verification server for a long while and has been working well. It has
also been used on jenkins.debian.net in the host.
https://f-droid.org/en/docs/Verification_Server/
It also includes GIT_TERMINAL_PROMPT, which also prevents the bad behavior,
which was added in git 2.3.
https://github.com/blog/1957-git-2-3-has-been-released
