[MacPorts] #68496: qt4-mac: fix the build for aarch64

[MacPorts]

#68496: qt4-mac: fix the build for aarch64
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 Reporter:  barracuda156  |      Owner:  michaelld
     Type:  defect        |     Status:  assigned
 Priority:  Normal        |  Milestone:
Component:  ports         |    Version:  2.8.1
 Keywords:  aarch64       |       Port:  qt4-mac
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 ​On Apple Silicon `qt4-mac` currently forces building for `x86_64`. It is
 desirable to have it built natively.

 Some found resources, possibly helpful:
 https://github.com/fluxer/katie
 https://github.com/flathub/shared-modules/tree/master/qt4

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Ticket URL: <https://trac.macports.org/ticket/68496>
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