According to some investigation creating "role" accounts avoids
migration problems when upgrading to certain macOS versions, so create
the build users to match that definition and remove the old ones if
present.
Role accounts require name starting with _ and UID in 200-400 range
This case will cause problems when existing files in /etc are replaced
instead of skipped with a warning, potentially breaking the nix install
in the process.
The nix.useDaemon option enables using a multi-user install without
managing the nix installation with nix-darwin. The following checks
apply to both cases.
All the checks are now aggregated in system.checks.text making it easy
to allow certain checks to be disabled as well as disabling them
alltogether if desired. eg.
# Disable all checks.
system.checks.text = mkForce "";
Fixes#117
