[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 mojca@…):

 Anything but (4) is acceptable.

 I'm sure that a lot of software doesn't work properly with Qt 5 yet. And
 some software doesn't work with Qt 4 any longer. We need to have both
 installed simultaneously to be able to do a soft transition and in order
 to be able to update the ports depending on Qt one-by-one.

 The goal is to make everything work with Qt 5 at some point in future, but
 that transition will definitely take time.

 (2) I would say that using a private prefix for Qt 5 is "good enough" for
 now unless the software would link against Qt 4 by accident (just because
 `-I${prefix}/include` contains Qt 4 for example).

 (3) If everything would stay under `${prefix}` we have problems at least
 with:
   * `${prefix}/bin/*`
   * `${prefix}/include/Qt*` (pointers to
 `${prefix}/Library/Frameworks/Qt*.framework/Headers`)
   * `${prefix}/include/Qt/*.h`
   * `${prefix}/Library/Frameworks/Qt*.framework/Versions/Current`
   * `${prefix}/lib/pkgconfig/*.pc`
   * `${prefix}/lib/*.(dylib|la|prl)` (some of them links to
 `${prefix}/Library/Frameworks/Qt*.framework/Qt*`)

 I have a feeling that moving these files around kind of defeats the
 purpose of having these files there in the first place (and having both in
 a private folder would be just as fine). But if someone can find a
 solution, that would be great.


 For the moment it would probably be acceptable to keep Qt 4 as the
 official version for a while, but put Qt to a private location (specified
 in the `PortGroup` and easily accessible via some variables), so that port
 maintainers could test their packages. What I don't know is whether this
 can be achieved without Qt 4 interfering.

 So if (2) and (3) are not easily doable, we might have to go for (1).

 Of course if anyone is brave enough to port everything to Qt 5 at once it
 would be ok to make a drastic move to Qt 5 only. But that would probably
 take too much effort.

-- 
Ticket URL: <https://trac.macports.org/ticket/44193#comment:4>
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