Bug#931646: Kmail crashes when I click on mail

[Bernhard Übelacker <bernhardu@mailbox.org>]

Hello Francis Laniel,
I am just looking at some crashes in some random packages,
and found this nouveau issue familiar.

I guess __pthread_cond_wait_common should be able to
handle a NULL for abstime - e.g. should "Block without a timeout".
    https://sources.debian.org/src/glibc/2.28-10/nptl/pthread_cond_wait.c/#L499

There are also some many more bugs reported that all end with these
nouveau_pushbuf_kick/nouveau_pushbuf_data calls triggering
that "Assertion `kref' failed.", that might be related:
    https://bugs.debian.org/927954
    https://bugs.debian.org/929130
    https://bugs.freedesktop.org/show_bug.cgi?id=91632
    https://bugs.freedesktop.org/show_bug.cgi?id=98039
    https://bugzilla.redhat.com/show_bug.cgi?id=1350275
    https://bugs.archlinux.org/task/59057
    https://bugreports.qt.io/browse/QTBUG-41242

The last one mentions as a workaround setting an
environment variable LIBGL_ALWAYS_SOFTWARE=1 or
QT_XCB_FORCE_SOFTWARE_OPENGL=1, maybe on of these still helps?

Kind regards,
Bernhard