Suggestion to support TeXDist symlink creation on Macs out-of-the-box

[Karl Berry]

        https://github.com/TeXLive-M/TeXDist/blob/master/scripts/postinstall

    My question is mostly: would it be possible to simplify this a bit and
    integrate it into tlmgr, so that users could select that (non-default)
    option during installation? 

tlmgr and the installer are two different things, although I suppose
most likely we'd want it both places, since everything seems to end up
in both.

As far as the installer goes, it does not sound too impossible to have
an option in the <O> menu (ditto GUIs) that would only appear on Macs
and perform the texdist postaction at the end. tlmgr could have
something that calls it also.

But let's not try to make all that happen right now. After the release,
when we can work on it without it being on the critical path. --thanks, karl.