new xcode build system and build failures

[Ken Cunningham]

> On Oct 1, 2018, at 1:00 PM, Rainer Müller <raimue at macports.org> wrote:
> 
> 
> One of the bugs with most impact seems to be that it always uses the
> user home from Directory Service and does not respect $HOME in the
> environment. The build system want to place
> ~/Library/Developer/Xcode/DerivedData/ there, but our sandbox prevents
> that. This seems to be the cause of many failed builds related to Xcode,
> as far as I could see in reported tickets.


I notice that if you open Xcode10 and look at 

Preferences -> Locations

the Derived Data default is exactly where you say it is above.

You can change this Derived Data location in several ways, including a large bunch of options in “Advanced”, one of which is called “Legacy”, interestingly.

So it seems that the default location for derived data may have changed in Xcode 10. 

I wonder if it is possible to change that default setting for the MacPorts user to one of the other options that might be more suitable via some 

"defaults write" command ...

Ken