Re: [Mingw-cross-env-list] Qt dependencies issues in master branch

[Mark Brand]

> Further to my previous post, I have now successfully installed qt5.
> Thanks. But I have noticed that the following packages have qt(4) as an
> explicit dependency:
> 

<snip>

> Aside from the wholly redundant

These packages, or at least certain enabled features of them require Qt.

> download and build of qt4 (due to the
> dependency), if I understand correctly these packages will /statically/

Yes, "statically" is what MXE does.

> link the qt4 libraries. If I develop an app using qt5 and try to link
> qwt, this will (try to?) link two versions of the same qt library in the
> resulting executable. This would seem a recipe for
> trouble/disaster/symbol collisions!

I doubt that qwt tried to link to both Qt versions, although that would be 
asking for trouble. If qt5 is already built, it's happily ignored. Read on..

> Any suggestions/comments on this? (I discovered this potential conflict
> by accident because I installed qwt thinking I would play with this
> really useful-looking package at some time, and I was bemused to see it
> building the qt4 package when I had already installed qt5. I don't want
> to use qwt now but, in the longer term, this appears to be an issue?) Is
> trying to maintain both qt4 and qt5 too complicated?

Apparently you expected qwt to find and use the qt5 you had already built. 
That's not how it works. The packages in MXE that depend on Qt, such as qwt, 
are configured now to use Qt 4. This is mostly because they were already 
configured that way before Qt 5 was released not that long ago. Not all 
packages that use Qt are ready for Qt 5. If you think that it makes sense 
now to migrate qwt or other packages to Qt 5 in MXE, please say so or 
propose a patch.

> BTW: Minor point. Installing qt5 does not create the triplet-decorated
> symbolic link to qmake, i686-pc-mingw32-qmake in .../usr/bin/, whereas
> installing qt4 does create this (really useful) link. Not a big deal but
> since somebody has been thoughtful enough to put it in the qt4 install...

The prefixed link to qmake is deprecated and could be removed at any time. 
As the documentation says, please invoke the desired qmake directly. Of 
course, you can adjust your PATH or add a link or alias of your own if you 
like.

Mark