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

[mascguy (Christopher Nielsen)]

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.

[Kyle Lanchman <k.lanchman@…>]

In 3cb5fcb16aaebfffaf60db6263d2371a01c1d7c1/macports-ports (master):

mint: fix build for macOS 10.14 and 10.15

mint's Makefile assumes the --arch flag is available on the `swift
build` command, which was added in Swift 5.3 / Xcode 12. This causes
builds to fail on machines with an older version of Xcode, even if
mint actually supports the Xcode version being used.

Closes: #64099