The ASTERIX development system runs in the built state, but for
external consumption Starlink insist we distribute our files into
the Starlink directory structure. This is done by moving the built
files from the build system directory xxx to /star/xxx/asterix.
Most files can simply be copied, but some scripts have to be edited.
When the install target moves the files is replaces the copies
in the build directories with soft links to the installed files. The
deinstall target destroys these links and moves the files back
to the build directories.