[Development] Change in qt/qtbase[5.8]: utilize configure results better in native builds

[René J.V. Bertin]

On Monday January 23 2017 10:30:50 Sérgio Martins wrote:

>Try running with QT_DEBUG_PLUGINS=1 and report back.

Hah, I think I was onto something, but it's not what I thought:

%> objdump -p systray-qt5/systray-qt5 | fgrep PATH
  RPATH                /opt/local/libexec/qt5/lib


As a result, all 5.8.0 platform plugins give an error like this:

%> env LD_LIBRARY_PATH=/opt/local/testing/libexec/qt5/lib QT_PLUGIN_PATH=/opt/local/testing/share/qt5/plugins QT_QPA_PLATFORM_PLUGIN_PATH=/opt/local/testing/share/qt5/plugins/platforms QT_DEBUG_PLUGINS=1 systray-qt5/systray-qt5
...
Found metadata in lib /opt/local/testing/share/qt5/plugins/platforms/libqxcb.so, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "xcb"
        ]
    },
    "className": "QXcbIntegrationPlugin",
    "debug": false,
    "version": 329728
}
In /opt/local/testing/share/qt5/plugins/platforms/libqxcb.so:
  Plugin uses incompatible Qt library (5.8.0) [release]
...

and then finally the process fails with

Found metadata in lib /opt/local/share/qt5/plugins/platforms/libqxcb.so, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "xcb"
        ]
    },
    "className": "QXcbIntegrationPlugin",
    "debug": false,
    "version": 329473
}
QLibraryPrivate::loadPlugin failed on "/opt/local/share/qt5/plugins/platforms/libqxcb.so" : "Cannot load library /opt/local/share/qt5/plugins/platforms/libqxcb.so: (/opt/local/libexec/qt5/lib/libQt5Core.so.5: version `Qt_5.8' not found (required by /opt/local/testing/libexec/qt5/lib/libQt5XcbQpa.so.5))"
This application failed to start because it could not find or load the Qt platform plugin "xcb"
in "/opt/local/testing/share/qt5/plugins/platforms".

IOW, I'll need to find a way to build that systray app in such a way that it contains RUNPATH instead of RPATH.

Is that what qmake 5.8.0 should do with the patch from this codereview in place? 

R.