[MacPorts] #64099: mint: build failure on 10.15 buildbot: swift doesn't support '--arch' for Xcode releases prior to 12.0

[MacPorts]

#64099: mint: build failure on 10.15 buildbot: swift doesn't support '--arch' for
Xcode releases prior to 12.0
---------------------+----------------------
 Reporter:  mascguy  |      Owner:  mascguy
     Type:  defect   |     Status:  assigned
 Priority:  Normal   |  Milestone:
Component:  ports    |    Version:  2.7.1
 Keywords:           |       Port:  mint
---------------------+----------------------
 Presently, this brand-new port is failing to build on the 10.15 buildbot,
 with the following error:

 {{{
 swift build --disable-sandbox -c release --arch arm64 --arch x86_64
 error: unknown option --arch; use --help to list available options
 }}}

 I believe this is related to the Xcode version on our 10.15 buildbot,
 which is 11.7. However, the port builds successfully on 10.15 with Xcode
 12.0.

 In any case, Kyle is in the process of enhancing this port, to add support
 for older macOS releases. (At least back to 10.14, and perhaps further.)
 That effort should resolve the issue, and this ticket can serve as a
 tracker for that work.

-- 
Ticket URL: <https://trac.macports.org/ticket/64099>
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