[MacPorts] #44193: qt: allow side by side installation of qt4-mac and qt5-mac

[MacPorts]

#44193: qt: allow side by side installation of qt4-mac and qt5-mac
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  Reporter:  mojca@…           |      Owner:  mcalhoun@…
      Type:  enhancement       |     Status:  new
  Priority:  Normal            |  Milestone:
 Component:  ports             |    Version:
Resolution:                    |   Keywords:
      Port:  qt4-mac, qt5-mac  |
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Comment (by michaelld@…):

 Replying to [comment:54 rjvbertin@…]:
 > Replying to [comment:53 michaelld@…]:
 > > Well, this is the way the Qt folks do it in Qt5; I just back-ported it
 to Qt4. I don't care if it is more or less efficient. If it's good enough
 for Qt5 then it's good enough for Qt4 (IMHO).
 > You may be right, but Qt5 has lots of other changes under the hood which
 may make this particular code path much less of a bottleneck that it
 *maybe* is in Qt4

 Also true. Bottom line is that this patch allows Qt4 to build on 10.11
 without resorting to using the 10.10 SDK; it seems to work correctly too.
 So, no matter the performance, this is a win at least for 10.11 users (who
 will be numerous shortly, since Apple just gives away the OS). I also
 doubt that the performance is very different between the original and this
 version, as the primary change is in
 "QCoreGraphicsPaintEngine::clearColorSpace", which, really, isn't likely
 to be used very often (do a grep though the qt4 source & you'll find a few
 references to this; grep those & you find almost no references). This
 method was removed in Qt5 sometime; apparently it really isn't used much
 if at all. Thus, I don't worry about performance, either.

-- 
Ticket URL: <https://trac.macports.org/ticket/44193#comment:55>
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