Intel TBB + Qt 4.7 = SIGABRT (Linux 64 bits)

[Sergio Callegari]

On some usages of dlopen, TBB creates keys that get wrongly deleted by QT so that when TBB attempts at deleting the key the application crashes.

This is reported on https://bugreports.qt.nokia.com//browse/QTBUG-10861

While there the issue is described as a marginal case, I think it is not. Most notably, it affects systems using nspluginwrapper with many widely used plugins. For instance, the bug makes nspluginwrapper crash when installed together with the googletalk plugin or some skypebutton plugin. See https://github.com/davidben/nspluginwrapper/issues/8 and our own https://bugs.launchpad.net/ubuntu/+source/nspluginwrapper/+bug/773020 that is getting tons of reports and tons of duplicates.

A fix is available for QT 4.8, but oniric appears to be shipping 4.7, so it is most likely affected by the bug.

Interestingly, the patch provided in https://bugreports.qt.nokia.com//browse/QTBUG-10861 at http://pastebin.com/webhbW7p is for qt 4.7 and can easily be applied to the ubuntu packages. Hence, please backport the fix from QT 4.8.