This has never been used (instead, `pre_build_script` was used), let's drop it. Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/34795>
This has never been used (instead, `pre_build_script` was used), let's drop it. Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/34795>