[ ] make sure that absolute paths written into the prefix are realpath-sanitized
[ ] make sure that re-targeting the ./usr symlink does not trigger a rebuild (i.e. make sure make considers target timestamps rather than symlink timestamps)
[ ] make sure that the build system and the build target are otherwise properly separated (i.e. no state of ./usr is tracked or implied outside of it)
realpath-sanitized./usrsymlink does not trigger a rebuild (i.e. make suremakeconsiders target timestamps rather than symlink timestamps)./usris tracked or implied outside of it)Low priority, but nice to have.