port "cask" -- installing prebuilt binaries

[Ken Cunningham]

A few more issues:

Handling supported_archs in binary-only ports. What if binary comes only as a universal binary, but the user asks for only one arch? We want that one binary to satisfy all the situations it can.

Handling universal requests. What if user asks for universal? If binary comes with three arches but user asks for only two? etc

Handling std library link checking? Binaries might come with all kinds of different linkages, including internal stdlibs (tenfourfox). Many will need link checking disabled, but some will need it enabled...

If we use only category to mark as a binary port, what if we have a binary port added (e.g. say lazarus) but then we later find out we can build that port on some systems? Then we want the binary lazarus moved to lazarus-binary, so we can have a real lazarus port that builds from source named lazarus. ( please ignore the fact we already have a lazarus port - this is just illustrative).

I'm back to using the name to mark binary ports. I believe we will regret not doing that in the end if we don't do it at the start.

K