[MacPorts] #57577: qt4-mac : set the graphicssystem via qtconfig

[MacPorts]

#57577: qt4-mac : set the graphicssystem via qtconfig
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  Reporter:  RJVB         |      Owner:  michaelld
      Type:  enhancement  |     Status:  assigned
  Priority:  Normal       |  Milestone:
 Component:  ports        |    Version:
Resolution:               |   Keywords:  haspatch
      Port:  qt4-mac      |
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Comment (by RJVB):

 Thanks for the confirmation. That means we can now cater to all
 possibilities:

 - reproduce the "legacy" behaviour (default graphics system for pure Qt4
 apps, raster for KDE4 apps)
 - impose native graphics on every Qt4 app
 - impose raster graphics on every Qt4 app

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Ticket URL: <https://trac.macports.org/ticket/57577#comment:27>
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