holding rust at a particular version

Is it possible, either within poudriere or using traditional ports,
to not have ports building fetching latest rust?

rust 1.76 is already installed. 1.77 is in the ports tree.
1.76 is the latest for -current on arm64 on the pkg builders.

if I go into the ports tree and build something needing rust,
it'll build 1.77 rust locally instead of using the already-installed 1.76.
which would tie the machine up for hours if not days if allowed to proceed.

Can this be avoided?

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