Arch Linux

Thanks for reporting this. I forgot the developer (Rui) propagates changes across all his stuff. Qt actually provides tools to select the version -- we select qt5 by default because it is current. You can select the version with QT_SELECT=$majorver or with a config file. [1]

I struggled with qsampler in AUR to come up with something sane but ended up manipulating configure. I will have to check whether it is the buildsystem that needs fixing or some obvious trick we're missing. In the meantime, please change your symlinks.

[1] https://wiki.archlinux.org/index.php/Qt#Installation

export QT_SELECT=4 doesn't work with qtractor - it's the way configure is looking for the libs that doesn't work with Arch's setup of qt libs.

My complain here is, your PKGBUILD doesn't work unless qt5 is removed or used in a chroot.

@Qt actually provides tools to select the version...
No reason than to place the libs in qt/ instead of qt5/

@I struggled with qsampler in AUR to come up with something sane...
As I did with qtractor - I've used:
sed 's/^ac_qtdirs="qt"/ac_qtdirs="qt4"/' -i configure

@export QT_SELECT=4 doesn't work with qtractor
Like I said, Rui propagates the same changes, so they're all affected. I didn't notice this earlier because builds are all done in chroots.

@your PKGBUILD doesn't work unless qt5 is removed or used in a chroot
Right, I shouldn't have mentioned symlinks; they have no effect at all. I actually meant to suggest following the qsampler hack or building in a chroot.

@No reason than to place the libs in qt/ instead of qt5/
Bring this up with the qt maintainer :) This is done with the qtchooser package, so file a report against that.

@As I did with qtractor
Yes, keep doing that for now until I get in touch with upstream.

So we'll go with our hack; there is no known better solution. [1]

[1] http://www.rncbc.org/drupal/node/753