I figured out halfway what is going on.
The link is missing, and that is due to the install script not
being executed, which in turn is due to the install script not
existing in the binary package tarball. This again is due to
the way I built the package. For some special reason, I delete
the files
.INSTALL
.pkgdb/+INSTALL
from the working directory and then let them being rebuilt (or
at least try to) by the command
make pre-install-script
However, this not seems to rebuild the installation script. I
am pretty sure that this *used* to work until recently.