Why doesn't USE_UNZIP use the base system unzip?

[Garrett Cooper]

    So... trying to trim down dependencies in a ports build and I'm
confused as to why unzip in base (it's been in base for ~5 years)
isn't a sufficient replacement for archivers/unzip in ports. It
doesn't seem like we're doing anything incredibly complicated with
archivers/unzip, so I would think that it would be a drop-in
replacement. Am I incorrect?
Thanks,
-Garrett

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