QtHaveModule

[Andreas Enge <andreas@enge.fr>]

Hello,

a little request for help, and a message to keep track of what I have tried
out...

The upgrade from Qt 5.5 to 5.6.1-1 broke owncloud-client and bitcoin-core.
Apparently qtwebkit was moved into its own, community released (whatever
this means) module. So I am trying to add a package for qtwebkit.

The configure phase ends with this message:
Encountered 2 configuration warning(s):
 ! QtQuick module not found, QML APIs will not be built
 ! Missing GStreamer or QtMultimedia, disabling HTML5 media element support
I added qtdeclarative (for the former) and qtmultimedia, but nothing changed.

The error messages come from
qtwebkit-opensource-src-5.6.1/Tools/qmake/mkspecs/features/features.prf:

    qtHaveModule(quick): WEBKIT_CONFIG += have_qtquick
    else: CONFIGURE_WARNINGS += "QtQuick module not found, QML APIs will not be built"
...
    # HTML5 Media Support for builds with GStreamer
    unix:!mac:!contains(QT_CONFIG, no-pkg-config) {
        packagesExist("glib-2.0 gio-2.0 gstreamer-1.0 gstreamer-plugins-base-1.0") {
            WEBKIT_CONFIG += video use_gstreamer
        } else: packagesExist("glib-2.0 gio-2.0 \'gstreamer-0.10 >= 0.10.30\' \'gstreamer-plugins-base-0.10 >= 0.10.30\'") {
            WEBKIT_CONFIG += video use_gstreamer use_gstreamer010
        }
        use?(gstreamer): WEBKIT_CONFIG += use_native_fullscreen_video
    }

    !enable?(video):qtHaveModule(multimediawidgets) {
        WEBKIT_CONFIG += video use_qt_multimedia
    }

    !enable?(video) {
        CONFIGURE_WARNINGS += "Missing GStreamer or QtMultimedia, disabling HTML5 media element support"
    }

This makes me think that "qtHaveModule" does not work; and I wonder whether
in our other Qt modules that have Qt modules as input, these are actually
detected correctly. Well, I tried qtsensors, and did not notice this problem.

I suspect that this is due to our installing the different modules into
separate output paths, which already caused problems, see commit
7972d8a2e98af6592050a37036c2c80a01358fcf. Nix should have the same problem;
they call a shell script "setup-hook.sh" that extends an environment variable
NIX_QT5_MODULES by the output path of each module. This is then used in a
complicated shell script setup-hook.sh of qtbase.

Assistance would be greatly appreciated!

Andreas