GitGateUpstream carries each entry's extra_hosts; a new
git_gate_aggregate_extra_hosts() merges them into one map for the
gate container's /etc/hosts. Same host -> same IP is harmless
duplication; same host -> different IPs is a manifest bug
(/etc/hosts is per-container, not per-upstream) and dies with
the conflicting upstream names.
DockerGitGate.start passes one --add-host host:ip per merged
entry on docker create. Empty map (the default) emits no flags
and is a no-op for bottles that don't need DNS overrides.
didericis
102e29ee77