Using qt59 instead of qt5 (latest release)

[Craig Treleaven]

> On Apr 4, 2018, at 8:33 AM, Vincent Habchi <vince at macports.org> wrote:
> 
> Hi there,
> 
> I recently wanted to experiment with linking one of the ports I maintain (Qgis3) with QT 5.9, if only to find out if 5.10 wasn’t the source of all the glitches and crashes everyone experiences with that application. 
> 
> However, in order to do so, I’d have to rebuild several dependents such as py36-qt5 or qwt-qt5 (inter alia). Are those able to deal with a Qt5 version other than the last one?
> 

I am considering a similar move for mythtv.28.  

Looking at qwt-qt5, I think you’re going to have a problem.  As the port now stands, it does not appear to support any Qt5 versions other than the latest:

$ port info qwt-qt5
qwt-qt5 @6.1.3_2 (graphics, science)
Sub-ports:            qwt-qt5-examples
…
Library Dependencies: qt5-qtbase, qt5-qtsvg, qt5-qttools
…

Another issue is Qt5 v. macOS versions.  When I last looked, a couple of months ago, it appears that Qt 5 has NO official support for macOS 10.13.  Has that changed?

Qt 5.7 and 5.8 were no longer officially supported.

Qt 5.6 is supported until next March (2019) but not on macOS 10.12 or later.

Qt 5.9 is supported until 2020 on 10.10, 10.11 and 10.12.  

I don’t follow the Qt5 project that closely; I don’t know what the practical implications of “official support’ really are.  It certainly appears that various versions of Qt5 “work” on High Sierra.  OTOH, I think there are interface problems with MythTV under Qt 5.10.  I hope these will go away by rolling back to, say Qt 5.6.  

BTW, out of about 2,900 MythTV Linux systems using Qt5 (in their voluntary reporting system), nearly 2,200 are running Qt 5.5.  Another 300 are running Qt 5.7.  Only 3 are running Qt 5.10.  A further 1,000 users are still running older versions of Myth that require Qt 4.

Craig