I have a very complex application that needs a directory in /usr. By complex, I mean it would take thousands of changes to rid the code of /usr references. It has to be done, but I need a newer OS X immediately. When I attempted to upgrade an older OS X system, it wiped this directory as part of the installation. If I run the csrutil disable on the system, place the /usr subdirectory back where it goes, will ongoing OS X security updates within the Mojave version (10.14, not OS major upgrades) purge the directory when applied, or leave it in place?