startupitem issue with unmounted volume (non-default prefix)

[Ryan Schmidt]

> On Jul 21, 2015, at 9:04 PM, Daniel J. Luke wrote:
>> On Jul 21, 2015, at 7:27 PM, Ryan Schmidt wrote:
>>> ok, so we should probably be copying the plist (instead of symlinking it - which is a lesson we should have already learned from back in the ‘images’ days) - and we likely also want something like the above.
>> 
>> I don't remember: any reason why we need a copy/symlink there? Why can't we just put the plist there (and only there)?
> 
> I believe it was a desire to have everything in $prefix (and maybe to facilitate when people have more than one install in different prefixes?)

But if you have multiple installs, you already have to set "startupitem_install no" and "startupitem_type none" in macports.conf on all but one of them. There would be no significant difference if we were to change MacPorts to install the plist file to its final destination directly, rather than to put a symlink there.