Previously, all extensions were compiled by default into one directory in a per-user cache location.
This PR emits each extension to the knossos build directory, under its own name.
This is a precursor to rebuilding extensions only when the C++ code or arguments have changed
Previously, all extensions were compiled by default into one directory in a per-user cache location. This PR emits each extension to the knossos build directory, under its own name. This is a precursor to rebuilding extensions only when the C++ code or arguments have changed