CMake has the ability to build itself it's own self-contained internal libraries, including libarchive, which tend to be very compatible versions.
We might someday have an option to make it do this for situations such as this maybe, but for now, you can try to do it manually. in the depends_lib-append section of the portfile, delete the line with the port:libarchive requirement. you can override just libarchive (look here <https://github.com/Kitware/CMake/blob/master/CMakeLists.txt> for the magic variables to use) or you can try just going down to the platform darwin 8 block (which is set up like this for Tiger) and try putting your version of darwin in there, whatever it is, to delete the --system-libs requirement and force cmake to build using it's internal libraries. You might need to monkey around a bit more to get it to work. if you really mess up and want to start over, do a "sudo port sync" and the portfiles will be put back to original status I hope this helps you out. -- K
