[MacPorts] #66039: lzma not building on macOS 12 when targeting 10.12

[MacPorts]

#66039: lzma not building on macOS 12 when targeting 10.12
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  Reporter:  lukaso  |      Owner:  ryandesign
      Type:  defect  |     Status:  assigned
  Priority:  Normal  |  Milestone:
 Component:  ports   |    Version:
Resolution:          |   Keywords:
      Port:  lzma    |
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Comment (by lukaso):

 It would be really helpful in order to use this for packaging of apps,
 which is my use case (GIMP). In this case I've dodged the problem by not
 needing the package anymore (poppler not requiring boost so not requiring
 lzma).

 What would it take to hack a change to legacysupport to make it work? I
 can't tell from the code where that would happen. Installing the legacy-
 support port was definitely not enough (not sure that's even what is
 expected here).

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Ticket URL: <https://trac.macports.org/ticket/66039#comment:6>
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