xcode builds, Xcode 10, and fixing the xcode PG

[Ken Cunningham]

Hello all,

As you know, a number of MacPorts' xcode builds have been broken by the new xcode build system that came with Xcode 10.

Maybe all of them, not sure. There are several underlying causes for this, I believe <https://trac.macports.org/ticket/57137#comment:25>.

I have been fixing these on a case-by-case basis as I came across them, or as people presented tickets for ports they asked to be fixed <https://trac.macports.org/ticket/57830>.

It was suggested that we stop doing this and instead fix the xcode PortGroup as a whole, obviously a great solution if possible. <https://github.com/macports/macports-ports/pull/4043>

I have outlined the steps that I thought might be taken to do this here <https://trac.macports.org/ticket/57137#comment:26> , but before I embark on the journey, I'd like to get some buy-in to the overall concept before getting bogged down in the minutiae, as I suspect there may be some unhappiness with what has to be done in that PG to fix MacPorts builds with Xcode 10. The available solutions do have some warts.

Or, as always, maybe somebody has some better idea!

All the best,

Ken