[MacPorts] #69653: mkvtoolnix-legacy: support Qt4 where Qt5 unavailable

[MacPorts]

#69653: mkvtoolnix-legacy: support Qt4 where Qt5 unavailable
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  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):

 Replying to [comment:2 barracuda156]:
 >
 > Ok, if no Qt4 support existed, then perhaps just disable qtgui for
 systems where it cannot be supported? And include qt5 PG conditionally.
 Building (at least for v81) requires qt regardless if qt gui is enabled or
 not.
 > P. S. By the way, what is the point of having a separate port, when
 existing one supports older systems with fallbacks already?
 https://github.com/macports/macports-
 ports/blob/d2f9f6bb49a41d643b1c975e2bcfd6805e0ca2d5/multimedia/mkvtoolnix/Portfile
 Because soon it will not. See https://trac.macports.org/ticket/69030.
 Submitting a legacy port is part of the preparation to update thee main
 port to v83 which is qt6 only.

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Ticket URL: <https://trac.macports.org/ticket/69653#comment:3>
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