With sincere apologies to Han Boetes, the dynamically linked copies of the system binaries have been removed from the system due to performance and manageability issues. For the sysutils/fakeroot port, there is a documented way to recompile these yourself, dynamically linked; you better be sure to only do that if /usr isn’t a separate filesystem, because otherwise, the programmes will be unable to find the dynamic link libraries or interpreter.
During an upgrade to the next snapshot, the files in these directories will be replaced by symbolic links. However, it is usually not instantly safe to remove them, because, for example, the /etc scripts use them, your user shell will be /usr/dbin/mksh, and the likes. So be careful wrt that directory. – A fresh MirOS installation however will no longer contain it.