These help static analysis and ubsan. We should eventually have all
functions annotated like this with a cimple check to make sure every
pointer has an explicit nullability annotation. The `nullable`
annotation does nothing in GCC, but will be used by cimple to validate
that every parameter has defined nullability.
Also added a whole bunch of logging that I needed while debugging the
issue. The solution in the end is that bootstrap needs to resolve IPs,
and getaddrinfo fails in the browser. Most of the time we bootstrap
against IPs anyway, so trying to parse as IP address first will shortcut
that.
* Use fully static build for the bootstrap daemon.
* Store a sha256sum of the binary in the repo.
* Updated documentation for it.
* Add support for fully static build in cmake.
* Enable the docker build on every PR, so we catch changes to the
checksum. I realise this is adding toil, but having the checksum is
valuable for security of released binaries.
