[MacPorts] #69653: mkvtoolnix-legacy: move fallback versions for legacy systems from mkvtoolnix port and do not force Qt5 unconditionally

[MacPorts]

#69653: mkvtoolnix-legacy: move fallback versions for legacy systems from
mkvtoolnix port and do not force Qt5 unconditionally
--------------------------------+-----------------------------------------
  Reporter:  barracuda156       |      Owner:  (none)
      Type:  defect             |     Status:  new
  Priority:  Normal             |  Milestone:
 Component:  ports              |    Version:  2.9.2
Resolution:                     |   Keywords:  snowleopard, leopard, tiger
      Port:  mkvtoolnix-legacy  |
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Comment (by i0ntempest):

 I took a closer look at the old change logs. Qt 5.9 is only required for
 building the GUI, so if we disable it older Qt 5 versions might work (as
 in the current port, v41 without GUI builds fine on 10.10 down to 10.6,
 and the 5.9 requirement was added with v40 for GUI).

 Seems like that the main port has multiple versions only because of system
 C++ library requirements. Currently the legacy port builds fine on 10.11
 and up. So maybe we CAN just disable GUI for 10.10 and below and v81 MIGHT
 work since we now have legacysupport libcxx.

-- 
Ticket URL: <https://trac.macports.org/ticket/69653#comment:6>
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