Comment 7 for bug 1285317

... "when" that library will be uninstalled..

You can reinstall it when the build is ended.

OSX kicad's building system is made to make those binaries "portable" between systems without the need of brew.
The last step of the building system will migrate and relocate in the bundle all the builded libraries.

There isn't a standard way to exclude lzma from wxpython command line sadly..