Upstream defect: acme.go is behind with_acme but acme_logger.go was not,
so go.uber.org/zap linked into every build even with ACME disabled. Only
acme.go references ACMELogWriter/ACMEEncoderConfig, so the twin gate is
behaviour-preserving; a with_acme build still compiles.
Marked lx:acme_logger_gate; upstream-PR candidate (drop the lx block on
rebase once merged). -94 KB on the router shaterd link.
omar
057fee8f96