Using an older port to make another port

[Michael]

How do I use an older port when making another one?

I followed the instructions for working with an older version of libarchive.
Going back to 97887a375da5d0f6abee018b145833aa02e2bda7 gave me libarchive @3.2.2_1 as a pre-built binary, no problems.

Now I'm trying to build cmake, which wants libarchive. I've got my git clone at the same (unchanged) checkout, but attempting to install it wants to rebuild libarchive.

In other words, the version of libarchive currently installed matches the version at 97887, but building cmake at 97887 ("sudo port install", from the devel/cmake directory) wants to build a fresh libarchive (apparently using the system install port tree).

How do I make this work?
And how do I then fix anything else that expects a cmake? (as it will probably try to use the system definition of cmake, which will use the system definition of libarchive, which will break).

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